Frequency mapping using drive-sense circuits

ABSTRACT

A data sensing circuit including a reference signal circuit, a reference signal combining circuit, drive-sense circuits, an array of sensors, sets of digital filters, and a processing module. The processing module provides a reference control signal to the reference signal circuit operable to generate a plurality of reference signals based on the reference control signal. The reference signal combining circuit transmits sets of reference signals to the drive-sense circuits operably coupled to an array of sensor. When the sensor is exposed to a condition, and is receiving the signal from the drive-sense circuits, an electrical characteristic of the sensor affects the signal, which is interpreted by the drive-sense circuit and converted to a digital signal to be filtered by the set of digital filters generating a frequency response for the array of sensors.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. § 120 as a continuation of U.S. Utility application Ser. No.17/249,260 entitled “DRIVE SENSE CIRCUIT WITH TRANSIENT SUPPRESSION”,filed Feb. 25, 2021, which is a continuation of U.S. Utility applicationSer. No. 16/195,349 entitled “DRIVE SENSE CIRCUIT WITH TRANSIENTSUPPRESSION”, filed Nov. 19, 2018, and issued on Mar. 2, 2021 as U.S.Pat. No. 10,935,585, all of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. UtilityPatent Application for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable.

BACKGROUND OF THE INVENTION Technical Field of the Invention

This invention relates generally to data communication systems and moreparticularly to sensed data collection and/or communication.

Description of Related Art

Sensors are used in a wide variety of applications ranging from in-homeautomation, to industrial systems, to health care, to transportation,and so on. For example, sensors are placed in bodies, automobiles,airplanes, boats, ships, trucks, motorcycles, cell phones, televisions,touch-screens, industrial plants, appliances, motors, checkout counters,etc. for the variety of applications.

In general, a sensor converts a physical quantity into an electrical oroptical signal. For example, a sensor converts a physical phenomenon,such as a biological condition, a chemical condition, an electriccondition, an electromagnetic condition, a temperature, a magneticcondition, mechanical motion (position, velocity, acceleration, force,pressure), an optical condition, and/or a radioactivity condition, intoan electrical signal.

A sensor includes a transducer, which functions to convert one form ofenergy (e.g., force) into another form of energy (e.g., electricalsignal). There are a variety of transducers to support the variousapplications of sensors. For example, a transducer is capacitor, apiezoelectric transducer, a piezoresistive transducer, a thermaltransducer, a thermal-couple, a photoconductive transducer such as aphotoresistor, a photodiode, and/or phototransistor.

A sensor circuit is coupled to a sensor to provide the sensor with powerand to receive the signal representing the physical phenomenon from thesensor. The sensor circuit includes at least three electricalconnections to the sensor: one for a power supply; another for a commonvoltage reference (e.g., ground); and a third for receiving the signalrepresenting the physical phenomenon. The signal representing thephysical phenomenon will vary from the power supply voltage to ground asthe physical phenomenon changes from one extreme to another (for therange of sensing the physical phenomenon).

The sensor circuits provide the received sensor signals to one or morecomputing devices for processing. A computing device is known tocommunicate data, process data, and/or store data. The computing devicemay be a cellular phone, a laptop, a tablet, a personal computer (PC), awork station, a video game device, a server, and/or a data center thatsupport millions of web searches, stock trades, or on-line purchasesevery hour.

The computing device processes the sensor signals for a variety ofapplications. For example, the computing device processes sensor signalsto determine temperatures of a variety of items in a refrigerated truckduring transit. As another example, the computing device processes thesensor signals to determine a touch on a touch screen. As yet anotherexample, the computing device processes the sensor signals to determinevarious data points in a production line of a product.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice in accordance with the present invention;

FIG. 3 is a schematic block diagram of another embodiment of a computingdevice in accordance with the present invention;

FIG. 4 is a schematic block diagram of another embodiment of a computingdevice in accordance with the present invention;

FIG. 5A is a schematic plot diagram of a computing subsystem inaccordance with the present invention;

FIG. 5B is a schematic block diagram of another embodiment of acomputing subsystem in accordance with the present invention;

FIG. 5C is a schematic block diagram of another embodiment of acomputing subsystem in accordance with the present invention;

FIG. 5D is a schematic block diagram of another embodiment of acomputing subsystem in accordance with the present invention;

FIG. 5E is a schematic block diagram of another embodiment of acomputing subsystem in accordance with the present invention;

FIG. 6 is a schematic block diagram of an embodiment of a drive sensecircuit in accordance with the present invention;

FIG. 6A is a schematic block diagram of another embodiment of a drivesense circuit in accordance with the present invention;

FIG. 7 is an example of a power signal graph in accordance with thepresent invention;

FIG. 8 is an example of a sensor graph in accordance with the presentinvention;

FIG. 9 is a schematic block diagram of another example of a power signalgraph in accordance with the present invention;

FIG. 10 is a schematic block diagram of another example of a powersignal graph in accordance with the present invention;

FIG. 11 is a schematic block diagram of another example of a powersignal graph in accordance with the present invention;

FIG. 11A is a schematic block diagram of another example of a powersignal graph in accordance with the present invention;

FIG. 12 is a schematic block diagram of an embodiment of a power signalchange detection circuit in accordance with the present invention;

FIG. 13 is a schematic block diagram of another embodiment of a drivesense circuit in accordance with the present invention;

FIG. 14 is a schematic block diagram of another embodiment of a drivesense circuit with a programmable reference signal generator inaccordance with the present invention;

FIG. 15 is a schematic block diagram of an example of a drive sensecircuit with a programmed reference signal generator in accordance withthe present invention;

FIG. 16 is a schematic block diagram of another example of a drive sensecircuit with a programmed reference signal generator in accordance withthe present invention;

FIG. 17 is a schematic block diagram of another example of a drive sensecircuit with a programmed reference signal generator in accordance withthe present invention;

FIG. 18 is a schematic block diagram of another example of a drive sensecircuit with a programmed reference signal generator in accordance withthe present invention;

FIG. 19 is a schematic block diagram of an embodiment of a data sensingcircuit in accordance with the present invention;

FIG. 20 is a schematic block diagram of another embodiment of a datasensing circuit in accordance with the present invention;

FIG. 21 is a schematic block diagram of an embodiment of a data circuitin accordance with the present invention;

FIG. 22 is a schematic block diagram of an embodiment of a datacommunication circuit in accordance with the present invention;

FIGS. 23-26A, and 26B are schematic block diagrams of examples ofvariable circuits of the data communication circuit in accordance withthe present invention;

FIG. 27 is a schematic block diagram of another embodiment of a datacircuit in accordance with the present invention;

FIG. 28 is a schematic block diagram of another embodiment of a datasensing circuit of a touch screen display in accordance with the presentinvention;

FIG. 29 is a schematic block diagram of an embodiment of a configurablesensing system in accordance with the present invention;

FIG. 30 is a schematic block diagram of another embodiment of aconfigurable sensing system in accordance with the present invention;

FIG. 30A is a schematic block diagram of an embodiment of a data sensingcircuit configurable to establish a frequency response of a sensor froma set of reference signals;

FIG. 30B is a schematic block diagram of another embodiment of a drivesense circuit in accordance with the present invention;

FIG. 30C is an example of a reference signal having a small magnitudewith a upper and lower rail voltage;

FIG. 30D is an example of a circuit diagram of an electrode modeled as adistributed RLC network in accordance with the present invention;

FIG. 30E is an example of a frequency response diagram for a distributedRLC network in accordance with the present invention;

FIG. 30F is an example of a block diagram of parallel electrodes inclose proximity interfering with each other;

FIG. 30G is an example of a frequency response of a sensor beinginterfered with;

FIG. 31A is a schematic block diagram of an embodiment of a couplingnetwork of a configurable sensing system in accordance with the presentinvention;

FIG. 31B is a schematic block diagram of an embodiment of a programmablereference signal unit of a configurable sensing system in accordancewith the present invention;

FIG. 32A is a diagram of an example of creating a reference signal inaccordance with the present invention;

FIG. 32B is a schematic diagram of an example select signal combinationfor a programmable sensing system in accordance with the presentinvention;

FIG. 33 is a logic diagram of a method of an example of determining afrequency mapping for a sensing system in accordance with the presentinvention;

FIG. 34 is a schematic block diagram of an example of a frequency bandincluding a plurality of channels available for a sensing system inaccordance with the present invention;

FIG. 35 is a schematic block diagram of an example of a sensing systemusing frequencies based on a frequency mapping in accordance with thepresent invention;

FIG. 36 is a schematic block diagram of another example of a sensingsystem using frequencies based on a frequency mapping in accordance withthe present invention;

FIG. 37 is a schematic block diagram of an embodiment of a sensingcircuit in accordance with the present invention;

FIG. 38 is a schematic block diagram of an embodiment of a signal sourcecircuit of the sensing circuit in accordance with the present invention;

FIG. 39 is a schematic block diagram of an embodiment of a transientcircuit of the sensing circuit in accordance with the present invention;

FIG. 40 is a schematic block diagram of another embodiment of atransient circuit of the sensing circuit in accordance with the presentinvention;

FIG. 41 is a schematic block diagram of another embodiment of a sensingcircuit in accordance with the present invention;

FIG. 42 is a schematic block diagram of another embodiment of a sensingcircuit in accordance with the present invention;

FIG. 43 is a schematic block diagram of another embodiment of a sensingcircuit in accordance with the present invention;

FIG. 44 is a schematic block diagram of another embodiment of a drivesense circuit in accordance with the present invention; and

FIG. 45 is a schematic block diagram of another embodiment of a drivesense circuit in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem 10 that includes a plurality of computing. devices 12-10, one ormore servers 22, one or more databases 24, one or more networks 26, aplurality of drive-sense circuits 28, a plurality of sensors 30, and aplurality of actuators 32. Computing devices 14 include a touch screen16 with sensors and drive-sensor circuits and computing devices 18include a touch & tactic screen 20 that includes sensors, actuators, anddrive-sense circuits.

A sensor 30 functions to convert a physical input into an electricaloutput and/or an optical output. The physical input of a sensor may beone of a variety of physical input conditions. For example, the physicalcondition includes one or more of, but is not limited to, acoustic waves(e.g., amplitude, phase, polarization, spectrum, and/or wave velocity);a biological and/or chemical condition (e.g., fluid concentration,level, composition, etc.); an electric condition (e.g., charge, voltage,current, conductivity, permittivity, eclectic field, which includesamplitude, phase, and/or polarization); a magnetic condition (e.g.,flux, permeability, magnetic field, which amplitude, phase, and/orpolarization); an optical condition (e.g., refractive index,reflectivity, absorption, etc.); a thermal condition (e.g., temperature,flux, specific heat, thermal conductivity, etc.); and a mechanicalcondition (e.g., position, velocity, acceleration, force, strain,stress, pressure, torque, etc.). For example, piezoelectric sensorconverts force or pressure into an eclectic signal. As another example,a microphone converts audible acoustic waves into electrical signals.

There are a variety of types of sensors to sense the various types ofphysical conditions. Sensor types include, but are not limited to,capacitor sensors, inductive sensors, accelerometers, piezoelectricsensors, light sensors, magnetic field sensors, ultrasonic sensors,temperature sensors, infrared (IR) sensors, touch sensors, proximitysensors, pressure sensors, level sensors, smoke sensors, and gassensors. In many ways, sensors function as the interface between thephysical world and the digital world by converting real world conditionsinto digital signals that are then processed by computing devices for avast number of applications including, but not limited to, medicalapplications, production automation applications, home environmentcontrol, public safety, and so on.

The various types of sensors have a variety of sensor characteristicsthat are factors in providing power to the sensors, receiving signalsfrom the sensors, and/or interpreting the signals from the sensors. Thesensor characteristics include resistance, reactance, powerrequirements, sensitivity, range, stability, repeatability, linearity,error, response time, and/or frequency response. For example, theresistance, reactance, and/or power requirements are factors indetermining drive circuit requirements. As another example, sensitivity,stability, and/or linear are factors for interpreting the measure of thephysical condition based on the received electrical and/or opticalsignal (e.g., measure of temperature, pressure, etc.).

An actuator 32 converts an electrical input into a physical output. Thephysical output of an actuator may be one of a variety of physicaloutput conditions. For example, the physical output condition includesone or more of, but is not limited to, acoustic waves (e.g., amplitude,phase, polarization, spectrum, and/or wave velocity); a magneticcondition (e.g., flux, permeability, magnetic field, which amplitude,phase, and/or polarization); a thermal condition (e.g., temperature,flux, specific heat, thermal conductivity, etc.); and a mechanicalcondition (e.g., position, velocity, acceleration, force, strain,stress, pressure, torque, etc.). As an example, a piezoelectric actuatorconverts voltage into force or pressure. As another example, a speakerconverts electrical signals into audible acoustic waves.

An actuator 32 may be one of a variety of actuators. For example, anactuator 32 is one of a comb drive, a digital micro-mirror device, anelectric motor, an electroactive polymer, a hydraulic cylinder, apiezoelectric actuator, a pneumatic actuator, a screw jack, aservomechanism, a solenoid, a stepper motor, a shape-memory allow, athermal bimorph, and a hydraulic actuator.

The various types of actuators have a variety of actuatorscharacteristics that are factors in providing power to the actuator andsending signals to the actuators for desired performance. The actuatorcharacteristics include resistance, reactance, power requirements,sensitivity, range, stability, repeatability, linearity, error, responsetime, and/or frequency response. For example, the resistance, reactance,and power requirements are factors in determining drive circuitrequirements. As another example, sensitivity, stability, and/or linearare factors for generating the signaling to send to the actuator toobtain the desired physical output condition.

The computing devices 12, 14, and 18 may each be a portable computingdevice and/or a fixed computing device. A portable computing device maybe a social networking device, a gaming device, a cell phone, a smartphone, a digital assistant, a digital music player, a digital videoplayer, a laptop computer, a handheld computer, a tablet, a video gamecontroller, and/or any other portable device that includes a computingcore. A fixed computing device may be a computer (PC), a computerserver, a cable set-top box, a satellite receiver, a television set, aprinter, a fax machine, home entertainment equipment, a video gameconsole, and/or any type of home or office computing equipment. Thecomputing devices 12, 14, and 18 will be discussed in greater detailwith reference to one or more of FIGS. 2-4 .

A server 22 is a special type of computing device that is optimized forprocessing large amounts of data requests in parallel. A server 22includes similar components to that of the computing devices 12, 14,and/or 18 with more robust processing modules, more main memory, and/ormore hard drive memory (e.g., solid state, hard drives, etc.). Further,a server 22 is typically accessed remotely; as such it does notgenerally include user input devices and/or user output devices. Inaddition, a server may be a standalone separate computing device and/ormay be a cloud computing device.

A database 24 is a special type of computing device that is optimizedfor large scale data storage and retrieval. A database 24 includessimilar components to that of the computing devices 12, 14, and/or 18with more hard drive memory (e.g., solid state, hard drives, etc.) andpotentially with more processing modules and/or main memory. Further, adatabase 24 is typically accessed remotely; as such it does notgenerally include user input devices and/or user output devices. Inaddition, a database 24 may be a standalone separate computing deviceand/or may be a cloud computing device.

The network 26 includes one more local area networks (LAN) and/or one ormore wide area networks WAN), which may be a public network and/or aprivate network. A LAN may be a wireless-LAN (e.g., Wi-Fi access point,Bluetooth, ZigBee, etc.) and/or a wired network (e.g., Firewire,Ethernet, etc.). A WAN may be a wired and/or wireless WAN. For example,a LAN may be a personal home or business's wireless network and a WAN isthe Internet, cellular telephone infrastructure, and/or satellitecommunication infrastructure.

In an example of operation, computing device 12-1 communicates with aplurality of drive-sense circuits 28, which, in turn, communicate with aplurality of sensors 30. The sensors 30 and/or the drive-sense circuits28 are within the computing device 12-1 and/or external to it. Forexample, the sensors 30 may be external to the computing device 12-1 andthe drive-sense circuits are within the computing device 12-1. Asanother example, both the sensors 30 and the drive-sense circuits 28 areexternal to the computing device 12-1. When the drive-sense circuits 28are external to the computing device, they are coupled to the computingdevice 12-1 via wired and/or wireless communication links as will bediscussed in greater detail with reference to one or more of FIGS.5A-5C.

The computing device 12-1 communicates with the drive-sense circuits 28to; (a) turn them on, (b) obtain data from the sensors (individuallyand/or collectively), (c) instruct the drive sense circuit on how tocommunicate the sensed data to the computing device 12-1, (d) providesignaling attributes (e.g., DC level, AC level, frequency, power level,regulated current signal, regulated voltage signal, regulation of animpedance, frequency patterns for various sensors, different frequenciesfor different sensing applications, etc.) to use with the sensors,and/or (e) provide other commands and/or instructions.

As a specific example, the sensors 30 are distributed along a pipelineto measure flow rate and/or pressure within a section of the pipeline.The drive-sense circuits 28 have their own power source (e.g., battery,power supply, etc.) and are proximally located to their respectivesensors 30. At desired time intervals (milliseconds, seconds, minutes,hours, etc.), the drive-sense circuits 28 provide a regulated sourcesignal or a power signal to the sensors 30. An electrical characteristicof the sensor 30 affects the regulated source signal or power signal,which is reflective of the condition (e.g., the flow rate and/or thepressure) that sensor is sensing.

The drive-sense circuits 28 detect the effects on the regulated sourcesignal or power signals as a result of the electrical characteristics ofthe sensors. The drive-sense circuits 28 then generate signalsrepresentative of change to the regulated source signal or power signalbased on the detected effects on the power signals. The changes to theregulated source signals or power signals are representative of theconditions being sensed by the sensors 30.

The drive-sense circuits 28 provide the representative signals of theconditions to the computing device 12-1. A representative signal may bean analog signal or a digital signal. In either case, the computingdevice 12-1 interprets the representative signals to determine thepressure and/or flow rate at each sensor location along the pipeline.The computing device may then provide this information to the server 22,the database 24, and/or to another computing device for storing and/orfurther processing.

As another example of operation, computing device 12-2 is coupled to adrive-sense circuit 28, which is, in turn, coupled to a senor 30. Thesensor 30 and/or the drive-sense circuit 28 may be internal and/orexternal to the computing device 12-2. In this example, the sensor 30 issensing a condition that is particular to the computing device 12-2. Forexample, the sensor 30 may be a temperature sensor, an ambient lightsensor, an ambient noise sensor, etc. As described above, wheninstructed by the computing device 12-2 (which may be a default settingfor continuous sensing or at regular intervals), the drive-sense circuit28 provides the regulated source signal or power signal to the sensor 30and detects an effect to the regulated source signal or power signalbased on an electrical characteristic of the sensor. The drive-sensecircuit generates a representative signal of the affect and sends it tothe computing device 12-2.

In another example of operation, computing device 12-3 is coupled to aplurality of drive-sense circuits 28 that are coupled to a plurality ofsensors 30 and is coupled to a plurality of drive-sense circuits 28 thatare coupled to a plurality of actuators 32. The generally functionalityof the drive-sense circuits 28 coupled to the sensors 30 in accordancewith the above description.

Since an actuator 32 is essentially an inverse of a sensor in that anactuator converts an electrical signal into a physical condition, whilea sensor converts a physical condition into an electrical signal, thedrive-sense circuits 28 can be used to power actuators 32. Thus, in thisexample, the computing device 12-3 provides actuation signals to thedrive-sense circuits 28 for the actuators 32. The drive-sense circuitsmodulate the actuation signals on to power signals or regulated controlsignals, which are provided to the actuators 32. The actuators 32 arepowered from the power signals or regulated control signals and producethe desired physical condition from the modulated actuation signals.

As another example of operation, computing device 12-x is coupled to adrive-sense circuit 28 that is coupled to a sensor 30 and is coupled toa drive-sense circuit 28 that is coupled to an actuator 32. In thisexample, the sensor 30 and the actuator 32 are for use by the computingdevice 12-x. For example, the sensor 30 may be a piezoelectricmicrophone and the actuator 32 may be a piezoelectric speaker.

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice 12 (e.g., any one of 12-1 through 12-x). The computing device 12includes a core control module 40, one or more processing modules 42,one or more main memories 44, cache memory 46, a video graphicsprocessing module 48, a display 50, an Input-Output (I/O) peripheralcontrol module 52, one or more input interface modules 56, one or moreoutput interface modules 58, one or more network interface modules 60,and one or more memory interface modules 62. A processing module 42 isdescribed in greater detail at the end of the detailed description ofthe invention section and, in an alternative embodiment, has a directionconnection to the main memory 44. In an alternate embodiment, the corecontrol module 40 and the I/O and/or peripheral control module 52 areone module, such as a chipset, a quick path interconnect (QPI), and/oran ultra-path interconnect (UPI).

Each of the main memories 44 includes one or more Random Access Memory(RAM) integrated circuits, or chips. For example, a main memory 44includes four DDR4 (4^(th) generation of double data rate) RAM chips,each running at a rate of 2,400 MHz. In general, the main memory 44stores data and operational instructions most relevant for theprocessing module 42. For example, the core control module 40coordinates the transfer of data and/or operational instructions fromthe main memory 44 and the memory 64-66. The data and/or operationalinstructions retrieve from memory 64-66 are the data and/or operationalinstructions requested by the processing module or will most likely beneeded by the processing module. When the processing module is done withthe data and/or operational instructions in main memory, the corecontrol module 40 coordinates sending updated data to the memory 64-66for storage.

The memory 64-66 includes one or more hard drives, one or more solidstate memory chips, and/or one or more other large capacity storagedevices that, in comparison to cache memory and main memory devices,is/are relatively inexpensive with respect to cost per amount of datastored. The memory 64-66 is coupled to the core control module 40 viathe I/O and/or peripheral control module 52 and via one or more memoryinterface modules 62. In an embodiment, the I/O and/or peripheralcontrol module 52 includes one or more Peripheral Component Interface(PCI) buses to which peripheral components connect to the core controlmodule 40. A memory interface module 62 includes a software driver and ahardware connector for coupling a memory device to the I/O and/orperipheral control module 52. For example, a memory interface 62 is inaccordance with a Serial Advanced Technology Attachment (SATA) port.

The core control module 40 coordinates data communications between theprocessing module(s) 42 and the network(s) 26 via the I/O and/orperipheral control module 52, the network interface module(s) 60, and anetwork card 68 or 70. A network card 68 or 70 includes a wirelesscommunication unit or a wired communication unit. A wirelesscommunication unit includes a wireless local area network (WLAN)communication device, a cellular communication device, a Bluetoothdevice, and/or a ZigBee communication device. A wired communication unitincludes a Gigabit LAN connection, a Firewire connection, and/or aproprietary computer wired connection. A network interface module 60includes a software driver and a hardware connector for coupling thenetwork card to the I/O and/or peripheral control module 52. Forexample, the network interface module 60 is in accordance with one ormore versions of IEEE 802.11, cellular telephone protocols, 10/100/1000Gigabit LAN protocols, etc.

The core control module 40 coordinates data communications between theprocessing module(s) 42 and input device(s) 72 via the input interfacemodule(s) 56 and the I/O and/or peripheral control module 52. An inputdevice 72 includes a keypad, a keyboard, control switches, a touchpad, amicrophone, a camera, etc. An input interface module 56 includes asoftware driver and a hardware connector for coupling an input device tothe I/O and/or peripheral control module 52. In an embodiment, an inputinterface module 56 is in accordance with one or more Universal SerialBus (USB) protocols.

The core control module 40 coordinates data communications between theprocessing module(s) 42 and output device(s) 74 via the output interfacemodule(s) 58 and the I/O and/or peripheral control module 52. An outputdevice 74 includes a speaker, etc. An output interface module 58includes a software driver and a hardware connector for coupling anoutput device to the I/O and/or peripheral control module 52. In anembodiment, an output interface module 56 is in accordance with one ormore audio codec protocols.

The processing module 42 communicates directly with a video graphicsprocessing module 48 to display data on the display 50. The display 50includes an LED (light emitting diode) display, an LCD (liquid crystaldisplay), and/or other type of display technology. The display has aresolution, an aspect ratio, and other features that affect the qualityof the display. The video graphics processing module 48 receives datafrom the processing module 42, processes the data to produce rendereddata in accordance with the characteristics of the display, and providesthe rendered data to the display 50.

FIG. 2 further illustrates sensors 30 and actuators 32 coupled todrive-sense circuits 28, which are coupled to the input interface module56 (e.g., USB port). Alternatively, one or more of the drive-sensecircuits 28 is coupled to the computing device via a wireless networkcard (e.g., WLAN) or a wired network card (e.g., Gigabit LAN). While notshown, the computing device 12 further includes a BIOS (Basic InputOutput System) memory coupled to the core control module 40.

FIG. 3 is a schematic block diagram of another embodiment of a computingdevice 14 that includes a core control module 40, one or more processingmodules 42, one or more main memories 44, cache memory 46, a videographics processing module 48, a touch screen 16, an Input-Output (I/O)peripheral control module 52, one or more input interface modules 56,one or more output interface modules 58, one or more network interfacemodules 60, and one or more memory interface modules 62. The touchscreen 16 includes a touch screen display 80, a plurality of sensors 30,a plurality of drive-sense circuits (DSC), and a touch screen processingmodule 82.

Computing device 14 operates similarly to computing device 12 of FIG. 2with the addition of a touch screen as an input device. The touch screenincludes a plurality of sensors (e.g., electrodes, capacitor sensingcells, capacitor sensors, inductive sensor, etc.) to detect a proximaltouch of the screen. For example, when one or more fingers touches thescreen, capacitance of sensors proximal to the touch(es) are affected(e.g., impedance changes). The drive-sense circuits (DSC) coupled to theaffected sensors detect the change and provide a representation of thechange to the touch screen processing module 82, which may be a separateprocessing module or integrated into the processing module 42.

The touch screen processing module 82 processes the representativesignals from the drive-sense circuits (DSC) to determine the location ofthe touch(es). This information is inputted to the processing module 42for processing as an input. For example, a touch represents a selectionof a button on screen, a scroll function, a zoom in-out function, etc.

FIG. 4 is a schematic block diagram of another embodiment of a computingdevice 18 that includes a core control module 40, one or more processingmodules 42, one or more main memories 44, cache memory 46, a videographics processing module 48, a touch and tactile screen 20, anInput-Output (I/O) peripheral control module 52, one or more inputinterface modules 56, one or more output interface modules 58, one ormore network interface modules 60, and one or more memory interfacemodules 62. The touch and tactile screen 20 includes a touch and tactilescreen display 90, a plurality of sensors 30, a plurality of actuators32, a plurality of drive-sense circuits (DSC), a touch screen processingmodule 82, and a tactile screen processing module 92.

Computing device 18 operates similarly to computing device 14 of FIG. 3with the addition of a tactile aspect to the screen 20 as an outputdevice. The tactile portion of the screen 20 includes the plurality ofactuators (e.g., piezoelectric transducers to create vibrations,solenoids to create movement, etc.) to provide a tactile feel to thescreen 20. To do so, the processing module creates tactile data, whichis provided to the appropriate drive-sense circuits (DSC) via thetactile screen processing module 92, which may be a stand-aloneprocessing module or integrated into processing module 42. Thedrive-sense circuits (DSC) convert the tactile data into drive-actuatesignals and provide them to the appropriate actuators to create thedesired tactile feel on the screen 20.

FIG. 5A is a schematic plot diagram of a computing subsystem 25 thatincludes a sensed data processing module 65, a plurality ofcommunication modules 61A-x, a plurality of processing modules 42A-x, aplurality of drive sense circuits 28, and a plurality of sensors 1-x,which may be sensors 30 of FIG. 1 . The sensed data processing module 65is one or more processing modules within one or more servers 22 and/orone more processing modules in one or more computing devices that aredifferent than the computing devices in which processing modules 42A-xreside.

A drive-sense circuit 28 (or multiple drive-sense circuits), aprocessing module (e.g., 41A), and a communication module (e.g., 61A)are within a common computing device. Each grouping of a drive-sensecircuit(s), processing module, and communication module is in a separatecomputing device. A communication module 61A-x is constructed inaccordance with one or more wired communication protocol and/or one ormore wireless communication protocols that is/are in accordance with theone or more of the Open System Interconnection (OSI) model, theTransmission Control Protocol/Internet Protocol (TCP/IP) model, andother communication protocol module.

In an example of operation, a processing module (e.g., 42A) provides acontrol signal to its corresponding drive-sense circuit 28. Theprocessing module 42 A may generate the control signal, receive it fromthe sensed data processing module 65, or receive an indication from thesensed data processing module 65 to generate the control signal. Thecontrol signal enables the drive-sense circuit 28 to provide a drivesignal to its corresponding sensor. The control signal may furtherinclude a reference signal having one or more frequency components tofacilitate creation of the drive signal and/or interpreting a sensedsignal received from the sensor.

Based on the control signal, the drive-sense circuit 28 provides thedrive signal to its corresponding sensor (e.g., 1) on a drive & senseline. While receiving the drive signal (e.g., a power signal, aregulated source signal, etc.), the sensor senses a physical condition1-x (e.g., acoustic waves, a biological condition, a chemical condition,an electric condition, a magnetic condition, an optical condition, athermal condition, and/or a mechanical condition). As a result of thephysical condition, an electrical characteristic (e.g., impedance,voltage, current, capacitance, inductance, resistance, reactance, etc.)of the sensor changes, which affects the drive signal. Note that if thesensor is an optical sensor, it converts a sensed optical condition intoan electrical characteristic.

The drive-sense circuit 28 detects the effect on the drive signal viathe drive & sense line and processes the affect to produce a signalrepresentative of power change, which may be an analog or digitalsignal. The processing module 42A receives the signal representative ofpower change, interprets it, and generates a value representing thesensed physical condition. For example, if the sensor is sensingpressure, the value representing the sensed physical condition is ameasure of pressure (e.g., x PSI (pounds per square inch)).

In accordance with a sensed data process function (e.g., algorithm,application, etc.), the sensed data processing module 65 gathers thevalues representing the sensed physical conditions from the processingmodules. Since the sensors 1-x may be the same type of sensor (e.g., apressure sensor), may each be different sensors, or a combinationthereof; the sensed physical conditions may be the same, may each bedifferent, or a combination thereof. The sensed data processing module65 processes the gathered values to produce one or more desired results.For example, if the computing subsystem 25 is monitoring pressure alonga pipeline, the processing of the gathered values indicates that thepressures are all within normal limits or that one or more of the sensedpressures is not within normal limits.

As another example, if the computing subsystem 25 is used in amanufacturing facility, the sensors are sensing a variety of physicalconditions, such as acoustic waves (e.g., for sound proofing, soundgeneration, ultrasound monitoring, etc.), a biological condition (e.g.,a bacterial contamination, etc.) a chemical condition (e.g.,composition, gas concentration, etc.), an electric condition (e.g.,current levels, voltage levels, electro-magnetic interference, etc.), amagnetic condition (e.g., induced current, magnetic field strength,magnetic field orientation, etc.), an optical condition (e.g., ambientlight, infrared, etc.), a thermal condition (e.g., temperature, etc.),and/or a mechanical condition (e.g., physical position, force, pressure,acceleration, etc.).

The computing subsystem 25 may further include one or more actuators inplace of one or more of the sensors and/or in addition to the sensors.When the computing subsystem 25 includes an actuator, the correspondingprocessing module provides an actuation control signal to thecorresponding drive-sense circuit 28. The actuation control signalenables the drive-sense circuit 28 to provide a drive signal to theactuator via a drive & actuate line (e.g., similar to the drive & senseline, but for the actuator). The drive signal includes one or morefrequency components and/or amplitude components to facilitate a desiredactuation of the actuator.

In addition, the computing subsystem 25 may include an actuator andsensor working in concert. For example, the sensor is sensing thephysical condition of the actuator. In this example, a drive-sensecircuit provides a drive signal to the actuator and another drive sensesignal provides the same drive signal, or a scaled version of it, to thesensor. This allows the sensor to provide near immediate and continuoussensing of the actuator's physical condition. This further allows forthe sensor to operate at a first frequency and the actuator to operateat a second frequency.

In an embodiment, the computing subsystem is a stand-alone system for awide variety of applications (e.g., manufacturing, pipelines, testing,monitoring, security, etc.). In another embodiment, the computingsubsystem 25 is one subsystem of a plurality of subsystems forming alarger system. For example, different subsystems are employed based ongeographic location. As a specific example, the computing subsystem 25is deployed in one section of a factory and another computing subsystemis deployed in another part of the factory. As another example,different subsystems are employed based function of the subsystems. As aspecific example, one subsystem monitors a city's traffic lightoperation and another subsystem monitors the city's sewage treatmentplants.

Regardless of the use and/or deployment of the computing system, thephysical conditions it is sensing, and/or the physical conditions it isactuating, each sensor and each actuator (if included) is driven andsensed by a single line as opposed to separate drive and sense lines.This provides many advantages including, but not limited to, lower powerrequirements, better ability to drive high impedance sensors, lower lineto line interference, and/or concurrent sensing functions.

FIG. 5B is a schematic block diagram of another embodiment of acomputing subsystem 25 that includes a sensed data processing module 65,a communication module 61, a plurality of processing modules 42A-x, aplurality of drive sense circuits 28, and a plurality of sensors 1-x,which may be sensors 30 of FIG. 1 . The sensed data processing module 65is one or more processing modules within one or more servers 22 and/orone more processing modules in one or more computing devices that aredifferent than the computing device, devices, in which processingmodules 42A-x reside.

In an embodiment, the drive-sense circuits 28, the processing modules,and the communication module are within a common computing device. Forexample, the computing device includes a central processing unit thatincludes a plurality of processing modules. The functionality andoperation of the sensed data processing module 65, the communicationmodule 61, the processing modules 42A-x, the drive sense circuits 28,and the sensors 1-x are as discussed with reference to FIG. 5A.

FIG. 5C is a schematic block diagram of another embodiment of acomputing subsystem 25 that includes a sensed data processing module 65,a communication module 61, a processing module 42, a plurality of drivesense circuits 28, and a plurality of sensors 1-x, which may be sensors30 of FIG. 1 . The sensed data processing module 65 is one or moreprocessing modules within one or more servers 22 and/or one moreprocessing modules in one or more computing devices that are differentthan the computing device in which the processing module 42 resides.

In an embodiment, the drive-sense circuits 28, the processing module,and the communication module are within a common computing device. Thefunctionality and operation of the sensed data processing module 65, thecommunication module 61, the processing module 42, the drive sensecircuits 28, and the sensors 1-x are as discussed with reference to FIG.5A.

FIG. 5D is a schematic block diagram of another embodiment of acomputing subsystem 25 that includes a processing module 42, a referencesignal circuit 100, a plurality of drive sense circuits 28, and aplurality of sensors 30. The processing module 42 includes a drive-senseprocessing block 104, a drive-sense control block 102, and a referencecontrol block 106. Each block 102-106 of the processing module 42 may beimplemented via separate modules of the processing module, may be acombination of software and hardware within the processing module,and/or may be field programmable modules within the processing module42.

In an example of operation, the drive-sense control block 104 generatesone or more control signals to activate one or more of the drive-sensecircuits 28. For example, the drive-sense control block 102 generates acontrol signal that enables of the drive-sense circuits 28 for a givenperiod of time (e.g., 1 second, 1 minute, etc.). As another example, thedrive-sense control block 102 generates control signals to sequentiallyenable the drive-sense circuits 28. As yet another example, thedrive-sense control block 102 generates a series of control signals toperiodically enable the drive-sense circuits 28 (e.g., enabled onceevery second, every minute, every hour, etc.).

Continuing with the example of operation, the reference control block106 generates a reference control signal that it provides to thereference signal circuit 100. The reference signal circuit 100generates, in accordance with the control signal, one or more referencesignals for the drive-sense circuits 28. For example, the control signalis an enable signal, which, in response, the reference signal circuit100 generates a pre-programmed reference signal that it provides to thedrive-sense circuits 28. In another example, the reference signalcircuit 100 generates a unique reference signal for each of thedrive-sense circuits 28. In yet another example, the reference signalcircuit 100 generates a first unique reference signal for each of thedrive-sense circuits 28 in a first group and generates a second uniquereference signal for each of the drive-sense circuits 28 in a secondgroup.

The reference signal circuit 100 may be implemented in a variety ofways. For example, the reference signal circuit 100 includes a DC(direct current) voltage generator, an AC voltage generator, and avoltage combining circuit. The DC voltage generator generates a DCvoltage at a first level and the AC voltage generator generates an ACvoltage at a second level, which is less than or equal to the firstlevel. The voltage combining circuit combines the DC and AC voltages toproduce the reference signal. As examples, the reference signal circuit100 generates a reference signal similar to the signals shown in FIG. 7, which will be subsequently discussed.

As another example, the reference signal circuit 100 includes a DCcurrent generator, an AC current generator, and a current combiningcircuit. The DC current generator generates a DC current a first currentlevel and the AC current generator generates an AC current at a secondcurrent level, which is less than or equal to the first current level.The current combining circuit combines the DC and AC currents to producethe reference signal.

Returning to the example of operation, the reference signal circuit 100provides the reference signal, or signals, to the drive-sense circuits28. When a drive-sense circuit 28 is enabled via a control signal fromthe drive sense control block 102, it provides a drive signal to itscorresponding sensor 30. As a result of a physical condition, anelectrical characteristic of the sensor is changed, which affects thedrive signal. Based on the detected effect on the drive signal and thereference signal, the drive-sense circuit 28 generates a signalrepresentative of the effect on the drive signal.

The drive-sense circuit provides the signal representative of the effecton the drive signal to the drive-sense processing block 104. Thedrive-sense processing block 104 processes the representative signal toproduce a sensed value 97 of the physical condition (e.g., a digitalvalue that represents a specific temperature, a specific pressure level,etc.). The processing module 42 provides the sensed value 97 to anotherapplication running on the computing device, to another computingdevice, and/or to a server 22.

FIG. 5E is a schematic block diagram of another embodiment of acomputing subsystem 25 that includes a processing module 42, a pluralityof drive sense circuits 28, and a plurality of sensors 30. Thisembodiment is similar to the embodiment of FIG. 5D with thefunctionality of the drive-sense processing block 104, a drive-sensecontrol block 102, and a reference control block 106 shown in greaterdetail. For instance, the drive-sense control block 102 includesindividual enable/disable blocks 102-1 through 102-y. An enable/disableblock functions to enable or disable a corresponding drive-sense circuitin a manner as discussed above with reference to FIG. 5D.

The drive-sense processing block 104 includes variance determiningmodules 104-1 a through y and variance interpreting modules 104-2 athrough y. For example, variance determining module 104-1 a receives,from the corresponding drive-sense circuit 28, a signal representativeof a physical condition sensed by a sensor. The variance determiningmodule 104-1 a functions to determine a difference from the signalrepresenting the sensed physical condition with a signal representing aknown, or reference, physical condition. The variance interpretingmodule 104-1 b interprets the difference to determine a specific valuefor the sensed physical condition.

As a specific example, the variance determining module 104-1 a receivesa digital signal of 1001 0110 (150 in decimal) that is representative ofa sensed physical condition (e.g., temperature) sensed by a sensor fromthe corresponding drive-sense circuit 28. With 8-bits, there are 28(256) possible signals representing the sensed physical condition.Assume that the units for temperature is Celsius and a digital value of0100 0000 (64 in decimal) represents the known value for 25 degreeCelsius. The variance determining module 104-b 1 determines thedifference between the digital signal representing the sensed value(e.g., 1001 0110, 150 in decimal) and the known signal value of (e.g.,0100 0000, 64 in decimal), which is 0011 0000 (86 in decimal). Thevariance determining module 104-b 1 then determines the sensed valuebased on the difference and the known value. In this example, the sensedvalue equals 25+86*(100/256)=25+33.6=58.6 degrees Celsius.

FIG. 6 is a schematic block diagram of a drive center circuit 28-acoupled to a sensor 30. The drive sense-sense circuit 28 includes apower source circuit 110 and a power signal change detection circuit112. The sensor 30 includes one or more transducers that have varyingelectrical characteristics (e.g., capacitance, inductance, impedance,current, voltage, etc.) based on varying physical conditions 114 (e.g.,pressure, temperature, biological, chemical, etc.), or vice versa (e.g.,an actuator).

The power source circuit 110 is operably coupled to the sensor 30 and,when enabled (e.g., from a control signal from the processing module 42,power is applied, a switch is closed, a reference signal is received,etc.) provides a power signal 116 to the sensor 30. The power sourcecircuit 110 may be a voltage supply circuit (e.g., a battery, a linearregulator, an unregulated DC-to-DC converter, etc.) to produce avoltage-based power signal, a current supply circuit (e.g., a currentsource circuit, a current mirror circuit, etc.) to produce acurrent-based power signal, or a circuit that provide a desired powerlevel to the sensor and substantially matches impedance of the sensor.The power source circuit 110 generates the power signal 116 to include aDC (direct current) component and/or an oscillating component.

When receiving the power signal 116 and when exposed to a condition 114,an electrical characteristic of the sensor affects 118 the power signal.When the power signal change detection circuit 112 is enabled, itdetects the affect 118 on the power signal as a result of the electricalcharacteristic of the sensor. For example, the power signal is a 1.5voltage signal and, under a first condition, the sensor draws 1 milliampof current, which corresponds to an impedance of 1.5 K Ohms. Under asecond conditions, the power signal remains at 1.5 volts and the currentincreases to 1.5 milliamps. As such, from condition 1 to condition 2,the impedance of the sensor changed from 1.5 K Ohms to 1 K Ohms. Thepower signal change detection circuit 112 determines this change andgenerates a representative signal 120 of the change to the power signal.

As another example, the power signal is a 1.5 voltage signal and, undera first condition, the sensor draws 1 milliamp of current, whichcorresponds to an impedance of 1.5 K Ohms. Under a second conditions,the power signal drops to 1.3 volts and the current increases to 1.3milliamps. As such, from condition 1 to condition 2, the impedance ofthe sensor changed from 1.5 K Ohms to 1 K Ohms. The power signal changedetection circuit 112 determines this change and generates arepresentative signal 120 of the change to the power signal.

The power signal 116 includes a DC component 122 and/or an oscillatingcomponent 124 as shown in FIG. 7 . The oscillating component 124includes a sinusoidal signal, a square wave signal, a triangular wavesignal, a multiple level signal (e.g., has varying magnitude over timewith respect to the DC component), and/or a polygonal signal (e.g., hasa symmetrical or asymmetrical polygonal shape with respect to the DCcomponent). Note that the power signal is shown without affect from thesensor as the result of a condition or changing condition.

In an embodiment, power generating circuit 110 varies frequency of theoscillating component 124 of the power signal 116 so that it can betuned to the impedance of the sensor and/or to be off-set in frequencyfrom other power signals in a system. For example, a capacitancesensor's impedance decreases with frequency. As such, if the frequencyof the oscillating component is too high with respect to thecapacitance, the capacitor looks like a short and variances incapacitances will be missed. Similarly, if the frequency of theoscillating component is too low with respect to the capacitance, thecapacitor looks like an open and variances in capacitances will bemissed.

In an embodiment, the power generating circuit 110 varies magnitude ofthe DC component 122 and/or the oscillating component 124 to improveresolution of sensing and/or to adjust power consumption of sensing. Inaddition, the power generating circuit 110 generates the drive signal110 such that the magnitude of the oscillating component 124 is lessthan magnitude of the DC component 122.

FIG. 6A is a schematic block diagram of a drive center circuit 28-alcoupled to a sensor 30. The drive sense-sense circuit 28-al includes asignal source circuit 111, a signal change detection circuit 113, and apower source 115. The power source 115 (e.g., a battery, a power supply,a current source, etc.) generates a voltage and/or current that iscombined with a signal 117, which is produced by the signal sourcecircuit 111. The combined signal is supplied to the sensor 30.

The signal source circuit 111 may be a voltage supply circuit (e.g., abattery, a linear regulator, an unregulated DC-to-DC converter, etc.) toproduce a voltage-based signal 117, a current supply circuit (e.g., acurrent source circuit, a current mirror circuit, etc.) to produce acurrent-based signal 117, or a circuit that provide a desired powerlevel to the sensor and substantially matches impedance of the sensor.The signal source circuit 111 generates the signal 117 to include a DC(direct current) component and/or an oscillating component.

When receiving the combined signal (e.g., signal 117 and power from thepower source) and when exposed to a condition 114, an electricalcharacteristic of the sensor affects 119 the signal. When the signalchange detection circuit 113 is enabled, it detects the affect 119 onthe signal as a result of the electrical characteristic of the sensor.

FIG. 8 is an example of a sensor graph that plots an electricalcharacteristic versus a condition. The sensor has a substantially linearregion in which an incremental change in a condition produces acorresponding incremental change in the electrical characteristic. Thegraph shows two types of electrical characteristics: one that increasesas the condition increases and the other that decreases and thecondition increases. As an example of the first type, impedance of atemperature sensor increases and the temperature increases. As anexample of a second type, a capacitance touch sensor decreases incapacitance as a touch is sensed.

FIG. 9 is a schematic block diagram of another example of a power signalgraph in which the electrical characteristic or change in electricalcharacteristic of the sensor is affecting the power signal. In thisexample, the effect of the electrical characteristic or change inelectrical characteristic of the sensor reduced the DC component but hadlittle to no effect on the oscillating component. For example, theelectrical characteristic is resistance. In this example, the resistanceor change in resistance of the sensor decreased the power signal,inferring an increase in resistance for a relatively constant current.

FIG. 10 is a schematic block diagram of another example of a powersignal graph in which the electrical characteristic or change inelectrical characteristic of the sensor is affecting the power signal.In this example, the effect of the electrical characteristic or changein electrical characteristic of the sensor reduced magnitude of theoscillating component but had little to no effect on the DC component.For example, the electrical characteristic is impedance of a capacitorand/or an inductor. In this example, the impedance or change inimpedance of the sensor decreased the magnitude of the oscillatingsignal component, inferring an increase in impedance for a relativelyconstant current.

FIG. 11 is a schematic block diagram of another example of a powersignal graph in which the electrical characteristic or change inelectrical characteristic of the sensor is affecting the power signal.In this example, the effect of the electrical characteristic or changein electrical characteristic of the sensor shifted frequency of theoscillating component but had little to no effect on the DC component.For example, the electrical characteristic is reactance of a capacitorand/or an inductor. In this example, the reactance or change inreactance of the sensor shifted frequency of the oscillating signalcomponent, inferring an increase in reactance (e.g., sensor isfunctioning as an integrator or phase shift circuit).

FIG. 11A is a schematic block diagram of another example of a powersignal graph in which the electrical characteristic or change inelectrical characteristic of the sensor is affecting the power signal.In this example, the effect of the electrical characteristic or changein electrical characteristic of the sensor changes the frequency of theoscillating component but had little to no effect on the DC component.For example, the sensor includes two transducers that oscillate atdifferent frequencies. The first transducer receives the power signal ata frequency of f1 and converts it into a first physical condition. Thesecond transducer is stimulated by the first physical condition tocreate an electrical signal at a different frequency f2. In thisexample, the first and second transducers of the sensor change thefrequency of the oscillating signal component, which allows for moregranular sensing and/or a broader range of sensing.

FIG. 12 is a schematic block diagram of an embodiment of a power signalchange detection circuit 112 receiving the affected power signal 118 andthe power signal 116 as generated to produce, therefrom, the signalrepresentative 120 of the power signal change. The affect 118 on thepower signal is the result of an electrical characteristic and/or changein the electrical characteristic of a sensor; a few examples of theaffects are shown in FIGS. 8-11A.

In an embodiment, the power signal change detection circuit 112 detect achange in the DC component 122 and/or the oscillating component 124 ofthe power signal 116. The power signal change detection circuit 112 thengenerates the signal representative 120 of the change to the powersignal based on the change to the power signal. For example, the changeto the power signal results from the impedance of the sensor and/or achange in impedance of the sensor. The representative signal 120 isreflective of the change in the power signal and/or in the change in thesensor's impedance.

In an embodiment, the power signal change detection circuit 112 isoperable to detect a change to the oscillating component at a frequency,which may be a phase shift, frequency change, and/or change in magnitudeof the oscillating component. The power signal change detection circuit112 is also operable to generate the signal representative of the changeto the power signal based on the change to the oscillating component atthe frequency. The power signal change detection circuit 112 is furtheroperable to provide feedback to the power source circuit 110 regardingthe oscillating component. The feedback allows the power source circuit110 to regulate the oscillating component at the desired frequency,phase, and/or magnitude.

FIG. 13 is a schematic block diagram of another embodiment of a drivesense circuit 28-b includes a change detection circuit 150, a regulationcircuit 152, and a power source circuit 154. The drive-sense circuit28-b is coupled to the sensor 30, which includes a transducer that hasvarying electrical characteristics (e.g., capacitance, inductance,impedance, current, voltage, etc.) based on varying physical conditions114 (e.g., pressure, temperature, biological, chemical, etc.).

The power source circuit 154 is operably coupled to the sensor 30 and,when enabled (e.g., from a control signal from the processing module 42,power is applied, a switch is closed, a reference signal is received,etc.) provides a power signal 158 to the sensor 30. The power sourcecircuit 154 may be a voltage supply circuit (e.g., a battery, a linearregulator, an unregulated DC-to-DC converter, etc.) to produce avoltage-based power signal or a current supply circuit (e.g., a currentsource circuit, a current mirror circuit, etc.) to produce acurrent-based power signal. The power source circuit 154 generates thepower signal 158 to include a DC (direct current) component and anoscillating component.

When receiving the power signal 158 and when exposed to a condition 114,an electrical characteristic of the sensor affects 160 the power signal.When the change detection circuit 150 is enabled, it detects the affect160 on the power signal as a result of the electrical characteristic ofthe sensor 30. The change detection circuit 150 is further operable togenerate a signal 120 that is representative of change to the powersignal based on the detected effect on the power signal.

The regulation circuit 152, when its enabled, generates regulationsignal 156 to regulate the DC component to a desired DC level and/orregulate the oscillating component to a desired oscillating level (e.g.,magnitude, phase, and/or frequency) based on the signal 120 that isrepresentative of the change to the power signal. The power sourcecircuit 154 utilizes the regulation signal 156 to keep the power signalat a desired setting 158 regardless of the electrical characteristic ofthe sensor. In this manner, the amount of regulation is indicative ofthe affect the electrical characteristic had on the power signal.

In an example, the power source circuit 158 is a DC-DC converteroperable to provide a regulated power signal having DC and ACcomponents. The change detection circuit 150 is a comparator and theregulation circuit 152 is a pulse width modulator to produce theregulation signal 156. The comparator compares the power signal 158,which is affected by the sensor, with a reference signal that includesDC and AC components. When the electrical characteristics is at a firstlevel (e.g., a first impedance), the power signal is regulated toprovide a voltage and current such that the power signal substantiallyresembles the reference signal.

When the electrical characteristics changes to a second level (e.g., asecond impedance), the change detection circuit 150 detects a change inthe DC and/or AC component of the power signal 158 and generates therepresentative signal 120, which indicates the changes. The regulationcircuit 152 detects the change in the representative signal 120 andcreates the regulation signal to substantially remove the effect on thepower signal. The regulation of the power signal 158 may be done byregulating the magnitude of the DC and/or AC components, by adjustingthe frequency of AC component, and/or by adjusting the phase of the ACcomponent.

It is noted that terminologies as may be used herein such as bit stream,stream, signal sequence, etc. (or their equivalents) have been usedinterchangeably to describe digital information whose contentcorresponds to any of a number of desired types (e.g., data, video,speech, text, graphics, audio, etc. any of which may generally bereferred to as ‘data’).

FIG. 14 is a schematic block diagram of an embodiment for providingdifferent reference signal waveforms for a drive-sense circuit. Thedrive-sense circuit 28-b includes power source circuit 154, regulationcircuit 152 and change detection circuit 150. Reference signal generator149 is coupled to change detection circuit 150 in order to providereference signal 157. Change detection circuit 150 also receives anaffect 160 of source signal 158 that is caused by sensor 30. The drivesense circuit functions to create a signal 120 that is representative ofthe affect the changes to the sensor 30 have on the source signal 158.The signal 120 is subsequently processed to interpret the changes of thesensor to determine conditions to which the sensor is exposed.

Depending on the environment of the sensor, the type of sensor, and/orthe data desired from the sensor, different refinements to stimulatingand gathering data from the sensor may be desired. For example, ifbinary data is needed from the sensor (e.g., it's on or off, thecondition its sensing is either “a” or “b”, etc.), then the sensitivity,linearity, and/or resolution are less significant factors. Thus, theprocessing module can program the reference signal generator 149 toproduce a reference signal 157 that is good for detecting binary datawith less regard for sensitivity, linearity, and/or resolution of thesensed data.

As another example, when the data from the sensor is more granular thanbinary data (e.g., multi-bit data, phase shift data, frequency shiftdata, etc.), then the sensitivity (e.g., signal to noise ratio, signallevel, etc.), linearity (e.g., substantially linear spacing betweeninterpretations of data values), and/or resolution (e.g., amount ofchange in the sensor as it corresponds to a different value of ameasured condition) of the sensed data becomes more significant.Accordingly, the processing module 42 can program the reference signalgenerator 149 to produce a reference signal 157 that enables the drivesense circuit to obtain a desired level of sensitivity, linearity,and/or resolution for the sensed data.

In an example of operation, the processing module 42 programs thereference signal generator 149 via one or more control signals 147 tooutput one of a plurality of reference signals 157. The processingmodule generates the control signal(s) 147 based on sensing factors ofsensor 30, which correlates to a desired level(s) of sensitivity,linearity, and/or resolution. In an embodiment, as the operatingenvironment changes for sensor 30, the processing module changes thewaveform of reference signal 157. The drive sense circuit 28 adjusts itsoperation to regulate the source signal 158 to substantially match theadjusted reference signal 157.

The sensing factors include one or more of correlated and uncorrelatednoise, sensor linearity, sensor sensitivity attributes (such as sensorsensitivity granularity), type of data being gathered (e.g., thepresence of moisture (such as a wet finger on a capacitive touch screensensor), a change in atmosphere, (such as the relative components of airexposed to sensor 30), humidity, etc.) degradation of the sensor 30 overtime, etc. Sensing factors can vary based on a sensing environmentand/or type of sensing by sensor 30. For example, if sensor 30 isassociated with a touch screen, a sensing factor is sensing the presenceor absence of finger capacitance, and/or the presence or absence of apen capacitance.

As a further example, a sensing factor can change when a user initiatesuse of a pen or use of a finger for touch sensing to provide moregranular information such as pressure, speed of movement, orientation ofthe finger or pen. In another example, noise attributes can be importantwhen sensor 30 is sensing pressure, accordingly a change in noise canhave an impact on the accuracy of the pressure determination and is,therefor a useful sense factor. Additional factors, such as thelinearity associated with sensor 30 over its range will be aconsideration that can be used to influence reference signal 157 fromreference signal generator 149.

Drive-sense circuit 28-b can also be coupled to multiple sensors andincorporate multiple combinations of reference signals 157 fromreference signal generator 149 to enable drive-sense circuit 28-b tosense and/or accommodate differing conditions for sensors 30. In anexample, processing module(s) 42 generate control signals 147 that causethe reference signal generator 149 to generate a plurality of referencesignals 157; one for each sensing factor associated with one or moresensors. For example, a reference signal for detecting the presence orabsence for each of a plurality of sensing factors and/or the level ofeach of the plurality of sensing factors. In another example, a singlesensor 30 may be sensed with a plurality of reference signals, allowingthe drive sense circuit to obtain different levels of information and/ordifferent information from a sensor. In an example, processing module 42generates a time and/or frequency divided control signal 147 to enableto the drive-sense circuit to accomplish multiple objectives. In anotherexample, multiple sensors 30 are coupled to drive-sense circuit 28-b ina time and/or frequency divided manner.

FIG. 15 is a schematic block diagram of an embodiment for providing areference signal waveform for a drive-sense circuit. In an example, asinusoidal waveform, such as oscillating component 124 is generated byreference signal generator 149, which is coupled to change detectioncircuit 150. Reference signal generator 149 can be a phase-locked loop(PLL) a crystal oscillator, a digital frequency synthesizer, and/or anyother signal source that can provide a sinusoidal signal of desiredfrequency, phase shift, and/or magnitude.

In general, a power source circuit 154 produces a source signal 158 thatis regulated to substantially match the sinusoidal reference signal 157.For example, the sinusoidal signal generated by reference signalgenerator 149 is useful when sensor 30 (such as from FIG. 14 ) is one ofa plurality of sensors sensing capacitance changes of a touch screendisplay. In such an environment, the use of a sinusoidal referencesignal is readily generating and also does not introduce harmonics thatmay adversely affect the operation of the drive sense circuit, the touchscreen operation of the display, and/or the di splay operation of thedisplay.

The output of power source circuit 154 (source signal 158) and referencesignal generator output (such as reference signal 157 of FIG. 14 ) arecoupled to the inputs of Op-amp 151, the output of which is coupled toanalog to digital converter (ADC) 212. Signal 120, which represents thesource signal change is output by ADC 212 which output is also input toregulation circuit 152 and converted by digital to analog converter(DAC) 214; the output of regulation circuit 152 is coupled to powersource circuit 154 to provide regulation signal 156 to power sourcecircuit 154.

The sinusoidal signal generated by reference signal generator 149 ofFIG. 14 is non-linear signal and therefore has non-linear resolution.FIG. 16 is a schematic block diagram of another embodiment for providinga reference signal waveform for a drive-sense circuit. In thisembodiment, the reference signal generator 149 generates a triangularwaveform. The triangle wave is a periodic, piecewise linear, acontinuous real function that contains only odd harmonics and can begenerated by using the convolution property of Fourier transforms toprovide better resolution with a linear waveform.

A reference signal 157 having a triangular waveform is beneficial whenthe drive sense circuit is measuring more than binary granularity dataof the sensor. For example, of the sensor is detecting humidity, ahumidity value is one of a plurality of potential values. With atriangular waveform, sensed values of humidity are more equally spacedin comparison to a sinusoidal waveform, thus providing bettersensitivity and/or resolution when interpreting the sensed value toobtain a humidity value.

FIG. 17 is a schematic block diagram of another embodiment for providinga reference signal waveform for a drive-sense circuit. Reference signalgenerator 149 generates a sawtooth waveform, which is another form ofnon-sinusoidal waveform illustrated in FIG. 16 . The sawtooth waveform,which can be considered an asymmetric triangle wave form, is similarlylinear and is relatively easy to generate and provides relatively higherresolution and/or sensitivity than a sinusoidal signal.

FIG. 18 is a schematic block diagram of another embodiment for providinga reference signal waveform for a drive-sense circuit. Reference signalgenerator 149 generates a square-wave signal, which is another form ofthe non-sinusoidal waveform illustrated in FIG. 16 . With thesquare-wave waveform, amplitude alternates at a steady frequency betweenfixed minimum and maximum values, with the same duration at minimum andmaximum. The square-wave waveform has linear resolution and is alsorelatively easy to generate.

For example, a square wave reference signal is beneficial when the drivesense circuit is measuring phase responses of the sensor 30. With eachtransition of the square wave, the sensor's electrical characteristicswill likely product a phase shift. As a specific example, when thesensor has a capacitor component, the voltage of a capacitor cannotinstantaneously change, but the capacitor's current can. This differenceproduces a phase shift that causes a transient adjustment to the sourcesignal. The signal 120 represents the transient adjustment, which cansubsequently be interpreted to determine a phase shift.

FIG. 19 is a schematic block diagram of an embodiment of a data sensingcircuit 200 that includes an analog time domain circuit 202, an analogto digital circuit 204, and a digital frequency domain circuit 206. Thedata sensing circuit 200 operates in the time domain on information thatis in the frequency domain. In general, the data sensing circuit 200generates digital data 216 based on an analog frequency domain signal210 (e.g., an analog signal with data in the frequency domain) and areference signal 208. The resulting digital data 216 may be the desiredoutput data or may require further processing to obtain the desired dataoutput.

In an example of operation, the analog time domain circuit 202 outputs asignal component of the analog frequency domain signal 210 to a device218. The analog time domain circuit 202 includes a regulated sourcecircuit to generate the signal component. In one embodiment, theregulated source circuit is a dependent current source that is regulatedto a specific current value based on the reference signal 208. Inanother embodiment, the regulated source circuit is a voltage circuit(e.g., a linear regulator, a DC-DC converter, a battery, etc.) thatgenerates a regulated voltage based on the reference signal 208.

The device 218 alters the signal component to produce the analogfrequency domain signal 210, where the altering of the signal componentat a particular rate to represent input data. The inverse of the datarate corresponds to the frequency of the analog frequency domain signal210; thus, the signal in the analog domain and the data is in thefrequency domain. As an example, the signal component produced by theanalog time domain circuit 202 is a DC voltage (e.g., 0.25 volts to 5volts or more), which corresponds to the reference signal 208. Thedevice 218 alters the signal component by varying the loading on thesignal component to affect the voltage and/or current of the signalcomponent thereby created the analog frequency domain signal 210 (e.g.,the signal component plus the effects of altering).

As a specific example, the device 218 changes its resistance at aparticular rate (e.g., 10 Hz to 100 MHz or more) to represent the inputdata. An increase in resistance decreases voltage for a constantcurrent, decreases current for a constant voltage, or decreases bothvoltage and current of the signal component. A decrease in resistanceincreases the voltage for a constant current, increases the current fora constant voltage, or increases both voltage and current of the signalcomponent. The increasing and decreasing of the resistance of the deviceat the particular rate is representative of the input data. The numberof different resistance levels corresponds to the data level, where Nequals the number of unique data values per cycle of the data rate,where N is an integer of 2 or more. For instance, when N=2, there aretwo data levels (e.g., a logic “0” for a first resistance and a logic“1” for a second resistance) and when N=10, there are ten data levels(e.g., 0 through 9).

As another example of producing the analog frequency domain signal 210,the signal component produced by the analog time domain circuit 202includes an oscillating component (e.g., a sine wave, a triangular wave,square wave, saw-tooth wave, etc. with a peak to peak voltage of a fewmillivolts to 5 volts or more having a frequency of a 100 Hz to 1 MHz ormore), which corresponds to the reference signal 208. In this example,the device changes its impedance (e.g., capacitance, inductance, and/orresistance) at a particular rate (e.g., fx of 10 Hz to 100 MHz or more)to represent the input data. An increase in impedance decreases voltagefor a constant current, decreases current for a constant voltage, ordecreases both voltage and current of the signal component. A decreasein impedance increases the voltage for a constant current, increases thecurrent for a constant voltage, or increases both voltage and current ofthe signal component. The increasing and decreasing of the impedance ofthe device at the particular rate is representative of the input data.

Continuing with the example of operation, the analog time domain circuit202 uses the reference signal 208 in comparison to the analog frequencydomain signal 210 to create an analog frequency domain error correctionsignal 212. The analog frequency domain error correction signal 212 isrepresentative of the error correction needed to keep the signalcomponent and hence the analog frequency domain signal 210 substantiallymatching the reference signal. The error correction is representative ofthe frequency domain data that is embedded in the altering of the signalcomponent.

The analog to digital circuit 204 (e.g., an “n”-bit analog to digitalconverter, where n is an integer equal to or greater than 1) convertsthe analog frequency domain error correction signal 212 into a digitalfrequency domain error correction signal 214. The error correction,which is representative of the frequency domain data, is substantiallypreserved in the digital domain.

The digital frequency domain circuit 206 operates in the frequencydomain to recover the digital data 216. For example, the digitalfrequency domain circuit 206 includes one or more finite impulseresponse (FIR) filters, one or more cascaded integrated comb (CIC)filters, one or more infinite impulse response (FIR) filters, one ormore decimation stages, one or more fast Fourier transform (FFT)filters, and/or one or more discrete Fourier transform (DFT) filters.

FIG. 20 is a schematic block diagram of another embodiment of a datasensing circuit 200 that includes an analog time domain circuit 202-1,an analog to digital circuit 204, a digital frequency domain circuit206; and a digital to analog feedback circuit 220. This data sensingcircuit 200 operates similarly to the data sensing circuit 200 of FIG.10 with the following differences. The feedback for regulating thesignal component via the regulated source circuit within the analog timedomain circuit 201-1 is from the digital to analog feedback circuit 220(e.g., an “n”-bit digital to analog converter, when n is an integerequal to or greater than 1).

FIG. 21 is a schematic block diagram of another embodiment of a datacircuit 230 that includes a drive sense circuit 28, a plurality ofdigital bandpass filters (BPF) circuits 232-236, and a plurality of datasources (1 through n). The drive sense circuit 28 produces a drivesignal component of a drive & sense signal 238 (e.g., the drive part ofsignal 238) based on the reference signal 208 as previously discussed.The data sources operate at different frequencies to embed frequencydomain data into the drive & sense signal 238 (e.g., the sense part ofsignal 238). Each of the data sources operates similarly to the device218 of FIG. 10 to embed the data into the signal 238 by varying theloading on the drive component of signal 238.

In an example of operation, data source 1 alters the drive signalcomponent of the drive & sense signal 238 at a first frequency f1; datasource 2 alters the drive signal component of the drive & sense signal238 at a second frequency f2; and data source n alters the drive signalcomponent of the drive & sense signal 238 at an “nth” frequency fn. Thedrive sense circuit 28 regulates the drive & sense signal 238 tosubstantially match the reference signal 208, which may be similar toreference signal 157 of one or more of FIGS. 14-18 .

The drive sense circuit 28 outputs a signal 120 that is representativeof changes to the drive & sense signal 238 based on the regulation ofthe drive & sense signal 238. Each of the digital BPF circuits 232receives the signal 120 and is tuned to extract data therefromcorresponding to one of the data sources. For example, digital BPFcircuit 232 is tuned to extract the data at frequency f1 of the datasource 1 to produce one or more digital values representing the firstdata 240. The second digital BPF circuit 234 is tuned to extract thedata at frequency f2 of the data source 2 to produce one or more digitalvalues representing the second data 242. The nth digital BPF circuit 236is tuned to extract the data at frequency fn of the data source n toproduce one or more digital values representing the nth data 244. Eachof the digital BPF circuits 232-236 includes one or more finite impulseresponse (FIR) filters, one or more cascaded integrated comb (CIC)filters, one or more infinite impulse response (FIR) filters, one ormore decimation stages, one or more fast Fourier transform (FFT)filters, and/or one or more discrete Fourier transform (DFT) filters.

FIG. 22 is a schematic block diagram of an embodiment of a datacommunication circuit 101 that includes a drive circuit 103, a variablecircuit 105, and a drive sense circuit 107. The drive circuit 103 may beimplemented in a variety of ways. For example, the drive circuitincludes one or more of an operational amplifier (op-amp), a comparator,a level shift circuit, another drive sense circuit, a digital to analogconverter, a modulator, an encoder, etc. The variable circuit 105 may beimplemented via one or more electrical components having one or morevariable electrical characteristics (e.g., resistance, reactance,impedance, voltage, current, capacitance, inductance, etc.) examples ofwhich are discussed in FIGS. 23-26B.

In an example of operation, the drive sense circuit 28 (which may beimplemented as previously discussed) generates a source signal 113 thatpowers the variable circuit 105. The variable circuit 105 varies loadingon the source signal 113 based on a drive signal 111 received from thedrive circuit 103. For example, the variable circuit changes anelectrical characteristic in accordance with the drive signal 111 tovary the loading on the source signal.

As a particular example, the variable circuit is a variable capacitorand varies its capacitance based on the drive signal. With the drivesignal 111 at a particular frequency, the impedance of the capacitor ischanging based on the drive signal. The drive sense circuit 28 detectsthe impedance change as a variance in the load on the source signal 113.The drive sense circuit 28 includes a closed loop feedback to regulatethe source signal 113; the amount of regulation is indicative of thechange in impedance.

The drive circuit 103 generates the drive signal 111 based on the inputdata 109. For example, the data input 109 is a binary stream of data ata given bit rate, where frequency of the drive signal 109 equals oneover the bit rate. The drive circuit 103 converts the binary stream ofdata into the drive signal where a logic “0” of the binary bit stream isrepresented by a first magnitude and/or phase of the drive signal and alogic “1” of the binary bit stream is represented by a second magnitudeand/or phase of the drive signal. Thus, the magnitude and/or phase ofthe drive signal toggles between the first level and the second level inaccordance with the binary values of the binary but stream.

As another example, the input data 109 is a multiple-bit digital value(e.g., three bits or more) that is received at a data rate. As aspecific example, the input data is a 4-bit word having 16 possiblevalues. The drive circuit 103 converts each 4-bit word of the input datainto one of sixteen magnitudes and/or phases based on the specific valueof the 4-bit word to produce the drive signal 111. Thus, the magnitudeand/or phase of the drive signal 111 varies between one of sixteenlevels based on the specific value of a 4-bit word and the frequency ofthe drive signal corresponds to one over the data rate.

As yet another example, the input data 109 is again a multiple-bitdigital value (e.g., three bits or more) that is received at a datarate. In this example, the drive circuit 103 converts a multiple-bitword of the input data into a number of single-bit words (e.g., createsa binary stream). As a specific example, a multiple-bit word includes 8bits, which the drive circuit converts into eight 1-bit words. One 1-bitword for each bit in the 8-bit word. As such, the drive signal includeseight binary values for each 8-bit word of the input data. Accordingly,the magnitude and/or phase of the drive signal toggles between the firstlevel and the second level in accordance with the binary values of thebinary but stream and the frequency of the drive signal corresponds toone over eight times the data rate of the 8-bit word.

As a further example, the drive circuit 103 modulates the input data 109in accordance with one or more modulation protocols (e.g., amplitudemodulation (AM), amplitude shift keying (ASK), pulse width modulation(PWM), phase shift keying (PSK), quadrature PSK (QPSK), etc.) to produceone or more modulated signals. As a specific example, the drive circuituses one or more modulation protocols to produce a modulated signalusing a single carrier frequency (e.g., f1). As another specificexample, the drive circuit 103 uses one or more modulation protocols toproduce two modulates signals using two carrier frequencies (e.g., f1and f2).

The drive circuit 103 provides the drive signal 111 to the variablecircuit 105, which changes one or more electrical characteristics (e.g.,impedance, voltage, current, resistance, reactance, phase, etc.) of thevariable circuit 105. The change in electrical characteristics of thevariable circuit 105 affects the source signal 113 by changing theloading on the drive sense circuit 107. The drive sense circuit 107interprets the effect on the source signal 113 to determine the changingelectrical characteristic(s) of the variable circuit 105. The changingelectrical characteristic(s) of the variable circuit 105 can besubsequently interpreted as discussed herein to recover the data input109.

FIGS. 23-26B are schematic block diagrams of examples of variablecircuit 105. While FIGS. 23-26B depict individual electrical componentsoperating as a variable circuit 105, variable circuit 105 may includeone or more, or a combination of, the electricals components of FIGS.23-26B depending on the nature of data (e.g., word size, data rate,etc.) the data communication circuit 101 is to receive.

In FIG. 23 , the variable circuit 105 is a variable resistor receiving adrive signal at a frequency “f1.” In an embodiment, the variableresistor includes one or more rheostats. The drive signal is an input tothe rheostat(s) that adjusts its resistance. In another embodiment, thevariable resistor includes a switching resistor network, where theswitching resistor network couples, based on the drive signal 111,resistors of the resistor network in parallel and/or in series toproduce desired resistance values.

In FIG. 24 , the variable circuit 105 is a variable capacitor receivinga drive signal at a frequency “f2.” In an embodiment, the variablecapacitor includes one or more varactors. The drive signal is an inputto the varactor(s) that adjusts its capacitance. In another embodiment,the variable capacitance includes a switching capacitance network, wherethe switching capacitance network couples, based on the drive signal111, capacitors of the capacitor network in parallel and/or in series toproduce desired capacitance values.

In FIG. 25 , the variable circuit 105 is a variable inductor receiving adrive signal at a frequency “fn.” In another embodiment, the variablecapacitance includes a switching inductor network, where the switchinginductor network couples, based on the drive signal 111, inductors ofthe inductor network in parallel and/or in series to produce desiredinductance values.

In FIG. 26A, the variable circuit 105 is a transistor receiving a drivesignal at a frequency “fn.” In an embodiment, the transistor is a fieldeffect transistor (FET) that varies the loading on the source signal 113based on the drive signal 111 being applied to the gate-source of theFET. The drive signal 111 is within a range to keep the FET operating inthe gain mode (e.g., in a linear mode prior to being fully turned on)and to avoid saturating the FET (e.g., avoid turning it fully on). Inanother embodiment, the variable circuit 105 includes a plurality oftransistors coupled in series and/or in parallel. In the embodiment, thedrive signal includes a plurality of components; one for eachtransistor.

With a transistor(s), the input signal can contain multiple frequencycomponents representative of the input data 109. For example, in FIG.26B, the variable circuit 105 is a transistor receiving a drive signalthat includes two frequency components: one at frequency “f1” and theother at frequency “f2.” As such, for a given word of the input data, aportion of the word is represented by the first frequency f1 and anotherportion of the word is represented by the second frequency f2.

FIG. 27 is a schematic block diagram of another embodiment of a datacircuit 250 that includes a plurality of drive circuits 203, a pluralityof variable circuits 205, and a drive sense circuit 28. A first drivecircuit 203 drives a first variable circuit 205 with first input data256 at a first frequency f1 and a second drive circuit 203 drives asecond variable circuit 205 with second input data 256 at a secondfrequency f2. The variable circuits varying the loading on the drive &sense signal 252 based on the respective drive signals.

The drive sense circuit 28 regulates the drive & sense circuit 252 tosubstantially match the reference signal 254, which includes a DCcomponent and/or an oscillating component. In accordance with theregulation, the drive sense circuit 28 produces a signal 120 thatrepresents changes to the drive & sense signal. In this example, thesignal 120 includes components at frequencies f1 and f2, which representerror correction corresponding to the two data inputs 256 and 258.

FIG. 28 is a schematic block diagram of another embodiment of a datasensing circuit of a touch screen display that includes a first drivesense circuit 28-1 coupled to a first electrode 85-c and a second drivesense circuit 28-2 coupled to a second electrode 85-r without a touchproximal to the electrodes. Each of the drive sense circuits include acomparator, an analog to digital converter (ADC) 130, a digital toanalog converter (DAC) 132, a signal source circuit 133, and a driver.For additional embodiments of a drive sense circuit see pending patentapplication entitled, “Drive Sense Circuit with Drive-Sense Line” havinga filing date of Aug. 27, 2018, and an application number of Ser. No.16/113,379.

As an example, a first reference signal 122-1 (e.g., analog or digital)is provided to the first drive sense circuit 28-1 and a second referencesignal 122-2 (e.g., analog or digital) is provided to the second drivesense circuit 28-2. The first reference signal includes a DC componentand/or an oscillating at frequency f1. The second reference signalincludes a DC component and/or two oscillating components: the first atfrequency f1 and the second at frequency f2.

The first drive sense circuit 28-1 generates a sensor signal 116 basedon the reference signal 122-1 and provides the sensor signal to thecolumn electrode 85-c. The second drive sense circuit generates anothersensor signal 116 based on the reference signal 122-2 and provides thesensor signal to the column electrode.

In response to the sensor signals being applied to the electrodes, thefirst drive sense circuit 28-1 generates a first sensed signal 120-1,which includes a component at frequency f1 and a component a frequencyf2. The component at frequency f1 corresponds to the self-capacitance ofthe column electrode 85-c and the component a frequency f2 correspondsto the mutual capacitance between the row and column electrodes 85-c and85-r. The self-capacitance is expressed as 1/(2πf1Cp1) and the mutualcapacitance is expressed as 1/(2πf2Cm_0).

Also, in response to the sensor signals being applied to the electrodes,the second drive sense circuit 28-2 generates a second sensed signal120-2, which includes a component at frequency f1 and a component afrequency f2. The component at frequency f1 corresponds to a shieldedself-capacitance of the row electrode 85-r and the component a frequencyf2 corresponds to an unshielded self-capacitance of the row electrode85-r. The shielded self-capacitance of the row electrode is expressed as1/(2πf1Cp2) and the unshielded self-capacitance of the row electrode isexpressed as 1/(2πf2Cp2).

With each active drive sense circuit using the same frequency forself-capacitance (e.g., f1), the row and column electrodes are at thesame potential, which substantially eliminates cross-coupling betweenthe electrodes. This provides a shielded (i.e., low noise)self-capacitance measurement for the active drive sense circuits. Inthis example, with the second drive sense circuit transmitting thesecond frequency component, it has a second frequency component in itssensed signal, but is primarily based on the row electrode'sself-capacitance with some cross coupling from other electrodes carryingsignals at different frequencies. The cross coupling of signals at otherfrequencies injects unwanted noise into this self-capacitancemeasurement and hence it is referred to as unshielded.

FIG. 29 is a schematic block diagram of a programmable sensing system151 that includes one or more processing modules 42, a drive-sensecircuit (DSC) array 141, a coupling network 145, a sensor array 143, anda programmable reference signal unit 153. The DSC array 141 includes aplurality of drive sense circuits (e.g., drive sense circuit 28 of oneor more other figures of this patent application). The sensor array 143includes a plurality of sensors 30 and/or a plurality of actuators 32.The sensors and/or actuators of the sensor array 143 may be affiliatedwith a single device (e.g., a touch screen, a touch screen display, aninteractive white board, etc.), with a plurality of devices (e.g.,various equipment of a manufacturing facility), or distributedthroughout a geographic area to monitor a variety of conditions (e.g.,temperature, humidity, atmospheric pressure, etc.).

The programmable reference signal unit 153 may be implemented in avariety of ways. For example, the programmable reference signal unit 153includes a plurality of selectable signal generators; each operable togenerate a different reference signal (e.g., different waveform,different frequency, different amplitude(s), etc.). The processingmodule enables one or more of the selectable signal generates based onthe reference signals it wants generated. Another example of theprogrammable reference signal unit 153 will be discussed with referenceto FIG. 31B. Yet another example of the programmable reference signalunit 153 will be discussed with reference to FIGS. 32A and 32B.

Since the drive sense circuit using a single line to supply power to andsense a sensor, the coupling network 145 includes connections to supportthe single line connections between one or more drive sense circuits andone or more sensors or actuators. The coupling network 145 may beimplemented in a variety of ways. For example, the coupling network 145includes a switching network (e.g., a crossbar switch, cross-pointswitch, matrix switch, etc.) that allows any one of the drive sensecircuits of the DSC array 141 to be coupled to any sensor or actuator ofthe sensor array 143. As another example, the coupling network 145includes a plurality of connections and a plurality of switches (e.g.,transistors, relays, etc.) coupling the drive sense circuits to thesensors and/or actuators. The processing module “opens” or “closes” theswitches to enable the desired coupling between desired drive sensecircuits and desired sensors and/or actuators. Yet another example ofthe coupling network will be discussed with reference to FIG. 31A.

In an embodiment, the processing module(s) 42, the drive-sense circuit(DSC) array 141, the coupling network 145, and the programmablereference signal unit 153 of the programmable sensing system 151 areimplemented on one or more dies of an integrated circuit (IC). Inanother embodiment, the drive-sense circuit (DSC) array 141, thecoupling network 145, and the programmable reference signal unit 147 153of the programmable sensing system 151 are implemented on one or moredies of an integrated circuit (IC). In yet another embodiment,processing module(s) 42, the drive-sense circuit (DSC) array 141, thecoupling network 145, at least one sensor or actuator of the sensorarray 143, and the programmable reference signal unit 153 areimplemented on one or more dies of an integrated circuit (IC).

In an example, the programmable reference signal unit 147 153 generatesa separate reference signal (such as reference signal 157 from FIG. 14 )to each desired drive-sense circuit in drive-sense circuit array 141based on the desired operation of the programmable sensing system 151and/or as the operating conditions of the system 151 changes. Forexample, the desired operation includes providing touch screen sensingfor indoor conditions (e.g., temperature, ambient lighting, humidity,etc.). As a further example, when the touch screen is taken outside, theenvironment changes (e.g., temperature changes, ambient lightingchanges, humidity changes, etc.). As a result of the environmentalchanges, the operating conditions are changed (e.g., change one or morereference signals (e.g., frequency, amplitude, shape, phase, etc.),using more sensors, use less sensors, coupling multiple drive sensecircuits to a sensor to obtain different information from the sensor,create a multiple frequency reference signal for a drive sense circuitto obtain different information from a sensor, etc.).

FIG. 30 is a schematic block diagram of a programmable sensing system151-1 that includes a digital filter circuit array 139, the processingmodule(s) 42, the drive-sense circuit (DSC) array 141, the couplingnetwork 145, the sensor array 143, a second coupling network 149, and aprogrammable reference signal unit 153. The digital filter array 139includes a plurality of digital filters that can be selectively coupledto drive sense circuits of the DSC array 141. A digital filter of thearray 139 includes one or more digital filtering stages, where a digitalfilter stage includes one or more of a finite impulse response (FIR)filter, an infinite impulse response (IIR) filter, comb filter, apolyphase filter, cascaded integrator (CIC) filter, a decimator, aninterpolator, bandpass filter, low pass filter, high pass filter, etc.

As a specific example, a digital filter is coupled to receive a signalfrom a drive sense circuit (e.g., a 1-bit output of a digital to analogconverter of the drive sense circuit). The digital filter is programmed,or is fixed, to have a first stage and a second stage. The first stageincludes an FIR filter and a decimator and the second stage includes oneor more of a discrete Fourier transform (DFT) filter, a fast Fouriertransform (FFT), a filter bank (such as an FFT filter bank), etc.

The second coupling network 149 includes selective coupling to coupleone or more drive sense circuits to one or more digital filters of thedigital filter array 139. The coupling network 149 may be implemented ina variety of ways. For example, the coupling network 149 includes aswitching network (e.g., a crossbar switch, cross-point switch, matrixswitch, etc.) that allows any one of the drive sense circuits of the DSCarray 141 to be coupled to any digital filter of the digital filterarray 143. As another example, the coupling network 149 includes aplurality of connections and a plurality of switches (e.g., transistors,relays, etc.) coupling the drive sense circuits to the digital filters.The processing module “opens” or “closes” the switches to enable thedesired coupling between desired drive sense circuits and desireddigital filters.

The coupling of drive sense circuits to sensors and/or actuators and theprogramming of the programmable reference signal unit 153 are asdiscussed with reference to FIG. 29 . With this embodiment, the digitalfiltering is programmable and/or selectable to provide furtherprogramming options for setting up, using, and modifying theprogrammable sensing system 151-1.

FIG. 30A is a schematic block diagram of an embodiment of a data sensingcircuit 123 that includes a reference signal circuit 100, a referencesignal combining circuit 99, drive-sense circuits 28, an array ofsensors 30, sets of digital filters 140 (one or more digital filters perset), and a processing module 42. The array of sensors 30 are useablefor a variety of conditions and/or are usable within a variety ofdevices. For example, paragraphs 62-64 describe various exampleconditions for which sensors are used and paragraph 193 describesvarious examples devices in which sensors can be used.

To mitigate the adverse effects of interfering signals on a sensor, oran array of sensors, the data sensing circuit 123 generates a frequencyresponse for the sensor and/or one or more frequency responses for thearray of sensors. In general, a frequency response of a sensor isregarding how the sensor responds to signals having different frequencycomponents and/or how the sensor responds to interfering signals havingdifferent frequency components. As such, when a frequency response ofsensor indicates that the sensor's performance is less than desired dueto an interfering signal and/or other characteristic of the sensor at aparticular frequency (or frequency band), the particular frequency (orfrequency band) is avoided and another frequency (or frequency band) isused to achieve the desired performance.

The data sensing circuit 123 generates one or more frequency responses145 for the array of sensors in a variety of ways. For example, the datasensing circuit 123 generates a first frequency response 145 for a firstsensor 30; a second frequency response for a second sensor 30; and soon. To generate the first frequency response of the first sensor, thereference signal circuit 100 generates one or more reference signals(ref sig 1, ref sig 2, etc.) in accordance with a reference controlsignal 147. As an example, each reference signal in a sinusoidal signalhave a unique frequency (e.g., ref sig 1 has a frequency of 100 KHz, refsig 2 has a frequency of 110 KHz). A reference signal may be a voltagesignal or a current signal.

The processing module 42 generates the reference control signal 147based on a desired precision and frequency band of the frequencyresponse for the first sensor. For example, if a high precisionfrequency response is desired, the reference control signal 147instructs the reference signal circuit to generate a significant numberof reference signals having frequencies that span a desired frequencyrange of the sensor and at frequency intervals to capture a substantialmajority of interfering signals. For example, the frequency range isfrom 100 KHz to 100 MHz at 10 KHz increments.

For the first sensor, the reference signal combining circuit 99 combinesthe reference signals into a first set of reference signals. Thereference signal combining circuit 99 may be implemented in a variety ofways. For example, the reference signal combining circuit 99 includes aswitching network (e.g., a crossbar switch, cross-point switch, matrixswitch, etc.). As another example, the reference signal combiningcircuit 99 includes a plurality of connections and a plurality ofswitches (e.g., transistors, relays, etc.). The processing module“opens” or “closes” the switches to enable the desired coupling of thereference signals. Alternatively, the reference signal combining circuit99 provides the reference signals of the first set to the first drivesense circuit (DSC) in a serial manner or combined serial and parallelmanner.

The first drive sense circuit 28 receives the first set of referencesignals and applies them to the first sensor. With reference to FIG.30B, the drive sense circuit 28 includes an op-amp, an analog to digitalconverter (ADC), a feedback circuit 220, and a controlled signal source98 (e.g., voltage or current source). The drive sense circuit 28operates to keep the input voltages of the op-amp at the same value.Thus, as the set of reference signals is inputted to one of the inputsof the op-amp, the op-amp, the feedback circuit, and the controlledsignal source 98 function to hold the voltage on the other input of theop-amp at the level of the set of reference signals.

FIG. 30C illustrates an example of a reference signal that includes a DC(direct current) component, and a AC (alternating current) component. Inthis example, the AC signal component has a small magnitude. Forinstance the magnitude is less than or equal to fifty percent of therail voltage of Vdd (power supply) and Vss (ground).

Returning to the discussion FIG. 30B, the output of the op-amp reflectsthe adjustments made by the DSC based on the frequency response of thesensor. The ADC converts the output of the op-amp to a digital signal.As an example, when the sensor is an electrode, it can be modeled as adistributed RLC (resistor-inductor-capacitor) circuit as shown in FIG.30D. The electrode responds to the set of reference signal to produce afrequency response, and example of which is shown in FIG. 30E. In thisexample, the frequency response has a corner frequency (cutofffrequency) which will vary depending on the characteristics of electrodeand has a resonant frequency (natural frequency of the system) values.

Returning to the discussion of FIG. 30A, the first set of digitalfilters receives the digital signal from the ADC of the drive sensecircuit. A digital filter of a set of digital filters includes one ormore of a finite impulse response (FIR) filter, an infinite impulseresponse (IIR) filter, comb filter, a polyphase filter, cascadedintegrator (CIC) filter, a decimator, an interpolator, bandpass filter,low pass filter, high pass filter, etc.

The set of digital filters (e.g., one or more filters, each tuned tocorrespond to the frequency of one of the reference signals) outputsfrequency dependent electrical characteristics of the sensor. Forexample, a frequency dependent electrical characteristic corresponds tothe ratio between the output of the sensor and an input of the sensor ata given frequency. As another example, a frequency dependent electricalcharacteristic corresponds to an impedance of the sensor at a givenfrequency.

The processing module 42 processes the frequency dependent electricalcharacteristics of a sensor to produce a frequency response for thesensor. The processing module 42 may produce the frequency responses ofthe sensor serially, in parallel, or a combination thereof. For example,when the processing module is generating the frequency responses ofmultiple sensors in parallel, the sensors are supplied with theirrespective sets of reference signals. Due to a variety of conditions,signals of one sensor may interfere with another sensor.

For example and with reference to FIG. 30F, two electrodes in closeproximity and at least one of them interferes with the other. Forinstance, at a particular frequency the signaling on one sensorinterferes (i.e., is coupled to) the other sensor. The desired signalingand the interfering signal are processed by the drive sense circuit toproduce a digital output.

The processing module processes the digital output of the interferedwith sensor to produce its frequency response. When the interference isof specific magnitude with respect to the desired signal (e.g., 1% ormore), it will adversely affect the frequency response of the sensor.For example, FIG. 30G illustrates a frequency response of sensor that,as a result of interference, has a notch in its frequency response. Whenthis occurs, the processing module 42 avoids using the frequency ofnotch for this particular sensor and selects frequencies that are notadversely affected.

FIG. 31A is a schematic block diagram of an example coupling network 145and/or 149 for a programmable sensing system. In the example, couplingnetwork uses a multiplexer/demultiplexer (mux/demux) arrangement tocouple sensors from sensor array 143 (not shown) to drive-sense circuitsof drive-sense circuit array 141 (not shown). The multiplexer (MUX)portion selectively forwards input signals from one or more sensors ofthe sensor array to the demux portion in serial and/or in parallel. Thedemultiplexer (demux) then forwards the input signals selectively to oneor more desired drive-sense circuits of drive-sense circuit array 141.

FIG. 31B is a schematic block diagram of an example programmablereference signal unit for a programmable sensing system. In an example,responsive to an environmental change processing module 42 transmitscontrol signal 147 to one or more reference signal generators 149 ofprogrammable reference signal unit 153. A reference signal generator 149may be implemented in a variety of ways as previously discussed withreference to FIGS. 14-18 . In an embodiment, the reference signalgenerator 149 is fixed to provide a specific reference signal having aspecific shape at a particular frequency, or frequencies. In anotherembodiment, the reference signal generator 149 is programmable by theprocessing module to provide a reference signal having a desired shapeat a desired frequency, or frequencies.

FIG. 32A is a graphical representation of an example generating anon-sinusoidal reference signal 157 (e.g., a sawtooth waveform, atriangular waveform, a square waveform, etc.). In general, anon-sinusoidal signal is a function of a plurality of sinusoidal signalshaving different frequencies (e.g., f1, f2, f3, . . . fn). For instance,a square wave is a function of sinusoidal signals based on the followingFourier equation:

${f(x)} = {\frac{4}{\pi}{\sum_{{n = 1},3,5,\ldots}^{\infty}{\frac{1}{n}\sin\left( \frac{n\pi x}{L} \right)}}}$

Within the programmable sensing system, the response of the digitalfilters is known either because it is or it is selected. With thisknowledge, the frequencies of sinusoidal signals that sum together toform a non-sinusoidal signal can be selected to fall in the leastattenuating frequency bands of the digital filter response (e.g., araised cosine, a comb filter, sin(x)/x. etc.). This helps preserveinformation of the non-sinusoidal signal (at least to a degree due tothe response of the filter).

FIG. 32B is a schematic diagram of an example of a programmablereference signal generator 149 that includes a plurality of sinusoidalsignal generators (e.g., PLLs, digital frequency synthesizers, crystaloscillators, etc.), a plurality of switches, and an adder. Each of thesinusoidal signal generates may be fixed to produce a sinusoidal signalat a specific frequency or programmable to generate a sinusoidal signalhaving a desired frequency.

Depending on the desired waveform of a reference signal, one or moreswitches are closed. For example, for a sinusoidal signal at aparticular frequency, one of the switches is closed for thecorresponding sinusoidal signal generator. For a square wave referencesignal, some or all of the switches are closed. The adder adds thesinusoidal signals to produce an approximate square wave signal. Theexactness of the square wave signal depends on the number of sinusoidalsignals used. In many applications for generating non-sinusoidalsignals, 4 or more sinusoidal signals are summed together.

FIG. 33 is a logic diagram of an example of a method of frequencymapping for a communication system that includes drive sense circuitscoupled to load devices, which includes sensors, actuators, and/or datasource circuits. Within this communication system, each of the drivesense circuits uses a reference signal (e.g., 157 of one or more ofFIGS. 14-18 ) that has one or more oscillating components and/or thedrive sense circuit's corresponding load device(s) communicates usingone or more oscillating components in their communication signals. Forefficient operation of the communication system, reference signalsand/or communication signals coupling to the drive sense circuits usingfrequencies such that the effects on each other is known and optimizedfor a desire result.

The method begins at step 315 where a processing module of thecommunication system determines whether there is desired information incross-coupling between load devices of the sensing system and/or desiredinformation in the cross-coupling between line of the drive sensecircuit. Information via cross-coupling is desirable for a variety ofreasons. For example, in a touch screen display, the electrodes of thetouch screen have a self-capacitance with respect to a common reference(e.g., ground, a common voltage, etc.) and also have a mutualcapacitance between physically proximal electrodes (e.g., crossing eachother, parallel to each other, etc.). As such, there is usefulinformation in the mutual capacitance, which is an effect of crosscoupling of electrodes.

As another example, cross-coupling between the load devices and/or thelines of the drive sense circuits (e.g., the drive and sense linecoupling a drive sense circuit to a load device) to determine afrequency spectrum noise pattern in the sensing system. As a specificexample, some frequencies of a frequency band have significantinterferers in the system, while other frequencies do not. As anotherspecific example, some load devices are more susceptible to interferencethan other load devices. With this information, frequency sensitivitieswithin the system are known and can be used to optimize the frequenciesthat are used. The frequency spectrum noise pattern can be updated asoften as needed in the communication system.

As yet another example, a first type of data is carried on the linesbetween the drive sense circuits and the load devices and a second typeof data is carried in the cross-coupling between the lines and/orbetween the load devices. As a specific example, data “x” is encodedinto “a”+“b”+“ab”, where encoded part “a” is conveyed on a first linebetween a first drive sense circuit and a first load device, encodedpart “b” is conveyed on a second line between a second drive sensecircuit and a second load device, and encoded part “ab” is conveyed inthe cross-coupling between the first and second lines and/or between thefirst and second load devices.

When information in cross-coupling between sensors of the sensing systemis not desired, the method continues at step 317 where the processingmodule determines a number of drive sense circuits in the system thatwill be used for a current operation (e.g., touch screen sensing, datacommunication, frequency spectral analysis, environment sensing, tactilestimulation, etc.). In some instances, all of the drive sense circuitswill be used. In other instances, less than all of the drive sensecircuits will be used. In these instances, the processing moduledetermines with drive sense circuits will be used in a variety of ways.For example, the processing module accesses a look up table where theoperation functions as an index to the look up table. As anotherexample, the processing module determines which drive sense circuits touse based on the load devices (e.g., the type of load device, the driverequirements of the load device, the sensitivity of the load device,etc.). Note that the drive sense circuits, while having a commontopology, can have different power levels, sensitivity, frequencyresponses, etc.

The method continues at step 319 where the processing module determineswhether different frequencies are required for the drive sense circuits.For example, the drive sense circuits may require different frequenciesto sense different features/data points and/or if different types ofsensors are present in the sensor array. As a specific example, when theload devices are independent capacitor sensors, the drives sensecircuits can use a common frequency for the reference signal. As anotherspecific example, when a drive sense circuit is coupled to a pluralityof load devices that are data source circuits, then communication witheach load device is allocated a unique frequency. As an extension of thecurrent specific example, other drive sense circuit that are eachcoupled to multiple data source circuits use the same multiplefrequencies as the first drive sense circuit. As an alternate extensionof the current specific example, other drive sense circuit that are eachcoupled to multiple data source circuits use different multiplefrequencies from those used by the first drive sense circuit.

When different frequencies are not required, the method continues tostep 321, where the processing module allocates a common frequency foruse by the drive sense circuits. The method continues at step 323 wherethe processing module sets digital filtering parameters of the digitalfiltering circuitry based on the common frequency. The digital filteringcircuit is discussed with reference to one or more of FIGS. 5A-5E,19-21, 29, and 30 .

When, at step 315, the processing module determines that there isdesired information in the cross-coupling, the method continues at step325 where the processing module determines the number of drive sensecircuits in the system. This is similar to step 317 and further includesthe consideration for cross-coupling information.

The method continues with step 327 where the processing moduledetermines a number of cross-couplings to sense per drive sense circuitin the sensing system. The determination may be done in a variety ofways. For example, the processing module determines that cross-couplingbetween all of the load devices is desired. As another example, theprocessing module determines that the cross-coupling between some of theload devices is desired. Selecting which cross-couplings of which loaddevices can be done in a variety of ways. For example, in a touch screendisplay, cross-coupling of electrodes (e.g., touch screen sensors) isselected when the electrodes are experiencing a change inself-capacitance due to a finger or pen touch. As another example, theprocessing module determines physical distance between the load devices.For load devices that are within a particular distance with respect toone and other, they are included in the count for cross-coupling. Forload devices that are not within the particular distance with respect toone and other, they are not included in the count for cross-coupling.

Continuing from step 327 or when different frequencies are required atstep 319, the method continues to step 329 where the processing moduledetermines the number of frequencies needed. The method continues atstep 331 where the processing module determines whether there are morefrequencies needed than there are available frequencies. A frequencyband 347 as shown in FIG. 34 includes a plurality of channels 349 andeach channel is centered at its own frequency (f1, f2, . . . fn). Thechannels are typically equally spaced (e.g., the difference in frequencybetween two adjacent channels is a fixed frequency offset). For example,the frequency band includes 120 channels, each spaced at 300 Hz startingat 300 Hz or an integer multiple thereof.

For a variety of reasons, one or more channels may be unavailable at agiven time. For example, the channel has a frequency that corresponds tothe frequency of a large interferer. As another example, a channel hasbeen allocated for a specific function. The remaining channels 349within the frequency band 347 are deemed to be available.

Returning to the logic diagram of FIG. 34 , when the there are enoughfrequencies (e.g., channels) the method continues at step 333 whereinthe processing module allocates frequencies to the drive sense circuitsin accordance with data sensing requirements. The method continues atstep 239 where the processing module sets digital filtering based on theallocated frequencies. This is similar to step 323, but for a pluralityof digital filters.

When more frequencies are required than available, the method continuesat step 337 where the processing module determines a frequency reusepattern. The frequency reuse pattern can be determined in a variety ofways. For example, the processing module accesses a look up table todetermine the frequency reuse pattern. As another example, in a largetouch screen display, the touch screen is divided into regions, whereeach region includes a sufficient number of drive sense circuits to usemost, if not, all of the available frequencies. In an embodiment, theregions of the touch screen are activated in a time division multiplexedmanner. In another embodiment, the regions of the touch screen areactivated in a spatial division multiplexed manner (e.g., they arephysically separate and the physical separation is used to identify aregion). As a further example, the load devices are grouped intoregions, where each region includes a sufficient number of drive sensecircuits to use most, if not, all of the available frequencies. Theregions can be activated in a time division multiplexed manner and/or aspatial division multiplexed manner.

The method continues with step 339 where the processing module allocatesfrequencies in accordance with the frequency reuse pattern. The methodcontinues with step 341 where the processing module sets digitalfiltering based on the frequency reuse pattern. This is similar to step323, but for a plurality of digital filters.

FIG. 35 is a schematic block diagram of an example of a sensing systemthat includes a plurality of drive sense circuits (DSCs) 28 and aplurality of sensors 353. A sensor 353 functions to convert a physicalinput into an electrical output and/or an optical output (e.g.,capacitor sensors, inductive sensors, accelerometers, piezoelectricsensors, light sensors, etc.). The drive sense circuits 28 provide aregulated source signal or a power signal to the sensors 353 via thedrive-sense line. An electrical characteristic of the sensor 353 affectsthe regulated source signal or power signal, which is reflective of thecondition (e.g., the flow rate, temperature, impedance change, pressure,etc.) that the sensor is sensing. The drive sense circuit 28 detects theeffect on the reference signal via the drive-sense line and processesthe affect to produce a signal representative of power change, which maybe an analog or digital signal.

Cross-coupling (e.g., due to the proximity of the sensors 353, parasiticcapacitance, etc.) can also affect the signal on the drive sense line ofthe drive sense circuits 28. Here, each drive sense circuit 28 has areference signal at a different frequency (e.g., f1, f2, f3, and f4) inaccordance with a frequency mapping plan such that the signal providedon its drive sense line has a corresponding frequency. Each drive sensecircuit 28 interprets the effect on the signal it provides to acorresponding sensor plus the effects of cross-coupling information. Forexample, out 1 is a signal including a dominant frequency f1 (e.g., thefrequency of its reference signal) and non-dominant cross-couplingfrequencies f2, f3, and f4 (e.g., the frequencies of the referencesignals of the other drive sense circuits); out 2 is a signal includinga dominant frequency f2 and non-dominant cross-coupling frequencies f1,f3, and f4; out 3 is a signal including a dominant frequency f3 andnon-dominant cross-coupling frequencies f1, f2, and f4; and out 4 is asignal including a dominant frequency f4 and non-dominant cross-couplingfrequencies f1, f2, and D.

The non-dominant frequencies provide information regardingcross-coupling and the environment. For example, in output 1, the f2frequency component provides information regarding the cross-couplingbetween sensors 353-1 and 353-2; the f3 frequency component providesinformation regarding the cross-coupling between sensors 353-1 and353-3; and the f4 frequency component provides information regarding thecross-coupling between sensors 353-1 and 353-4. Note only does thenon-dominant frequencies provide information about the cross-coupling,it provides information about the reference signals of the other drivesense circuits. Note that data may be modulated into the referencesignals for conveyance to one or more other drive sense circuits.

FIG. 36 is a schematic block diagram of an example of the sensing systemthat includes a plurality of drive sense circuits (DSCs) 28. Each drivesense circuit 28 interprets the effects on the common drive-sense linecaused by the other drive sense circuits. A drive sense circuit 28provides data onto the drive-sense line via its reference signal. Forexample, each reference signal has its own frequency (f1-f4 in thisexample) and modulates data onto its reference signal. As a specificexample, reference signal at f1 includes a sinusoidal signal having afrequency at f1. Data is modulated on the sinusoidal signal by amplitudemodulation (AM), by amplitude shift keying (ASK), phase shift keying(PSK), or other modulation scheme.

The other drive sense circuits “regulate out” the effects of thereference signal at f1 as previously discussed. The amount of regulationcorresponds to the changing of the reference signal at f1, which equatesto the data modulated thereon. Each drive sense circuit performssimilarly with respect to the others' modulated reference signal toreceive the modulated data from the other drive sense circuits. Thefrequencies allocated to the drive sense circuits are done in accordancewith a frequency mapping plan.

FIG. 37 is a schematic block diagram of a sensing circuit 201 thatincludes a transient circuit 203 and a signal source circuit 205 coupledto a sensor 211. The signal source circuit 205, when enabled, provides asignal 221 to the sensor 211 via a conductor (e.g., a wire, a metaltrace on printed circuit board, etc.). The signal 221 includes one ormore of a direct current (DC) component and an oscillating component.The signal 221 is similar to power signal 116 as discussed withreference to FIGS. 6-7 and 9-11A.

In an example of operation, the sensor is exposed to one or moreconditions 213. The condition may be one or more of a physicalcondition, an electrical condition, a biological condition, a mechanicalcondition and an optical condition. For example, the sensor 211 is acapacitance sensor that, when exposed to a touch of a finger, changesits impedance. When the sensor 211 is exposed to the condition 213 andis receiving the signal 221, an electrical characteristic (e.g., animpedance, a voltage, a current, etc.) of the sensor 211 affects 219 thesignal 221. For example, with the impedance of a capacitive sensorchanging due to the touch of a finger and the current of the signalbeing regulated, the voltage across the sensor changes.

Further, when the sensing circuit 201 is in a noisy environment,transient noise 215 is created. For example, in a liquid crystal display(LCD) touch screen display, the toggling of gate lines (e.g., 25 volts)and/or data lines (e.g., 15 volts) of sub-pixels creates noise. Thisnoise couples into the signal 221 via sub-pixel electrodes. When thenoise is of sufficient level (e.g., within 80 dBm or less of the signal,which can adversely affect the signal to noise ratio), it causes thesignal 221 to be a noisy signal 217.

In furtherance of the above example, an LCD touch screen display for atablet, a phone, a television, a monitor, etc., has a resolution of1080×1920, which means it has 1080 rows of pixels and 1920 columns ofpixels. Each pixel includes a plurality of sub-pixels, so that there are3×1920=5,760 drive lines. In operation, one row of pixels is enabled ata time and all of 5,760 drives lines being enabled at the same time.With a refresh rate of 60 Hz, the 1080 rows are cycled through every1/60th of a second. This creates a very noisy environment for touchscreen sensing.

As a specific example, a sensing circuit 201 that drives and senses oneelectrode of the LCD touch screen display produces the signal 221 tohave a power of −20 dBm. Without noise 215, the noise floor for thesensing circuit 201 is of −120 dBm. Thus, a signal to noise ratio (SNR)is 100 dB. When noise 215 is present and it has a magnitude of 40 dBm,the noise floor (a sum of noise and interferers) increases to −80 dBm,which causes the SNR to decrease by 40 dB to 60 dB. As the SNRdecreases, the sensing circuit's ability to accurately sense the affect219 on the signal 221 is reduced.

The transient circuit 203 operates to produce a compensation signal 207to mitigate the effects of the noise 215 on the conductor when the noiseexceeds a threshold (e.g., −100 dBm or greater). For example, thetransient circuit 203 produces the compensation signal 207 by comparingthe noisy signal 217 with a representation of the noisy signal (e.g., adelayed representation of the noisy signal 217). When the noisy signalcompares unfavorably with the representation of the noisy signal (e.g.,is greater than the representation signal by a threshold value), thetransient circuit supplies the compensation signal 207 to the conductorthat is carrying the signal 221 to the sensor. The compensation signal207 (which has a level corresponding to the level at which the noisysignal compares unfavorably with the representation of the noisy signal)combines with the noisy signal 217 to mitigate the adverse effects ofthe noise 215.

When the noisy signal compares unfavorably with the representation ofthe noisy signal at a first level, the transient circuit supplies afirst level of the compensation signal (e.g., a first level of current)to the conductor. As another example, when the noisy signal comparesunfavorably with the representation of the noisy signal at a secondlevel, the transient circuit supplies a second level (e.g., differentthan the first) of the compensation signal to the conductor. Thetransient circuit is described in further detail in reference to FIGS.39-40 .

FIG. 38 is a schematic block diagram of an example of a signal sourcecircuit 205 that includes a power source circuit 231, a change detectioncircuit 235 and a regulation circuit 233. The power source circuit 231is operable to source at least one of a voltage and a current to thesensor to produce a signal 221 or to produce a power signal as thesignal 221. For instance, the power source circuit 231 produces signal221 based on a regulation signal 237. The change detection circuit 235,when enabled, is operable to detect the effects on the signal as aresult of the electrical characteristic (e.g., an impedance, a voltage,a current, etc.). The change detection circuit 235 is further operableto generate a signal 209 that is representative of change to the signalbased on the detected effect on the signal. When enabled, the regulationcircuit 233 is operable to generate a regulation signal 237. Theregulation signal 237 regulates one or more of the DC component to adesired DC level and the oscillating component to a desired oscillatinglevel. In general, the signal source circuit 205 operates similarly tothe drive sense circuit 28 as discussed herein.

FIG. 39 is a schematic block diagram of an example of a sensing systemthat includes a load 241 (e.g., a sensor 30), a drive sense circuit 28,and a transient circuit 203. The transient circuit 203 includes a delaycircuit 243, an operational amplifier (op amp) 245, and a dependentsupply source 247. The delay circuit 243 may be implemented in a varietyof ways. As an example, the delay circuit 243 includes one or moreresistors, one or more inductors and capacitors one or more. As aspecific example, the delay circuit is one of a low-pass filter, abandpass filter, a comb filter, a notch filter, a Chebyshev filter, aButterworth filter, a Bessel filter and an Elliptic filter. In anotherexample, the delay circuit includes a resistor and a capacitor.

In an example of operation, noise (e.g., thermal, excess charge, gateline switching noise, drive line switching noise, etc.) couples to asignal to produce a noisy signal 217. The delay circuit 243 delays thenoisy signal 217 in accordance with its delay properties to produce adelayed signal 179. For example, the delay circuit includes aresistor-capacitor (RC) circuit, which has a time constant of R*C and acutoff frequency of 1/(2*π*RC) (i.e., its delay properties). As aspecific example, if R=80 K Ohms and C=1 picofarad (pF) capacitor, thenthe cutoff frequency is about 2 megahertz (MHz) and the time constant(RC) is approximately 80 nanoseconds.

Continuing with the example of operation, the operational amplifier 245produces a compensation signal 207 based on the noisy signal 217 and itsdelayed representation 179. For example, the compensation signal 207will be negligible in comparison to the signal 221 when the noise 215 islow (e.g., less than −100 dBm). As the noise 215 increases, its effecton the signal 221 increases to the point where transients are present onthe noisy signal 217. When the transients are of sufficient size (e.g.,are not filtered out by the delay circuit 243), the compensation signalincreases in value.

As the compensation signal increases in value (or decreases in valuedepending on the polarity of the op amp 245), the dependent supplysource 247 produces a supply (e.g., a current, a voltage, etc.). Theproduced supply is inversely proportional to the transients on the noisysignal 217; thereby effectively cancelling the transients. As thetransients increase, the produced supply increases to continue tosubstantially cancel the transients, or at least render the transientsnegligible.

FIG. 40 is a schematic block diagram of another embodiment of atransient circuit 203. The transient circuit 203 includes a plurality ofintegrators 251 (alternatively a plurality of low pass filters), aplurality of operational amplifiers 245, and a plurality of dependentsupply sources 247-1 and -2. In an example of operation, when a supply(e.g., voltage) on the line changes rapidly (e.g. transient) thedifferential circuit operates to mitigate the rapid change so that thedrive sense circuit 28-b maintains a normal operating condition. Themitigation may be done by pulling up on the signal 221 by supply source247-1 (e.g., sourcing a current) or by pulling down on the signal 221 bysupply source 247-2 (e.g., sinking a current).

In a specific example, toggling of data lines or gate lines adds anamount of charge onto a capacitance of the load 241 (e.g., capacitanceassociated with electrodes of an LCD touch screen display). Adrive-sense circuit 28-b provides the signal 221 to one of theelectrodes (e.g., load 241 in the present figure), which is subject tothe noise produced by the toggling of gate and data lines. The transientcircuit 203 operates to track the excess charge in the capacitance ofthe electrode due to the noise and remove at least some of the excesscharge before it can substantially affect operation of the drive-sensecircuit.

FIG. 41 is a schematic block diagram of an example of a sensing circuitthat includes a transient circuit 203, a comparator 265, a dependentcurrent source 247, an analog to digital converter (ADC) 263 and adigital to analog converter (DAC) 261. The ADC 263 is one of: a flashADC, a successive approximation ADC, a ramp-compare ADC, a WilkinsonADC, an integrating ADC, a delta encoded ADC, and/or a sigma-delta ADC.The DAC 261 is one of a sigma-delta DAC, a pulse width modulator DAC, abinary weighted DAC, a successive approximation DAC, and/or athermometer-coded DAC.

In an example of operation, the dependent supply source 247 is poweredby a DC source (e.g., DC in) and generates a regulated source signal 271based the analog regulation signal 267. The regulated source signal 271is provided to a load (e.g., a sensor, an electrode of a touch screendisplay, etc.). The load affects 271 the signal 271, which is comparedto a reference source signal 273 by the comparator 265. The comparator265, the ADC 263, and the DAC 216 function to keep the regulated signal271 substantially matching the reference source signal 273. The errorcorrection to do this is representative of the effect on the signal,which corresponds to a change of the load.

The analog to digital converter 263 converts the comparison signal 277into a digital signal 269, which corresponds to the error correction andis representative of the affect 275 on the signal 271. The DAC 261converts the digital signal 269 into an analog regulated signal 267based on the compensation signal 207. The transient circuit 203 operatesas previously discussed to produce the compensation signal 207.

FIG. 42 is a schematic block diagram of another embodiment of a sensingcircuit that includes the transient circuit 203, the comparator 265, thedependent current source 247, the analog to digital converter (ADC) 263and the digital to analog converter (DAC) 261 of FIG. 41 . The sensingcircuit further includes an alternating current (AC) coupling capacitor255. The AC coupling capacitor 255 couples the transient circuit 203with the output of the DAC 261 to produce the analog regulation signal267. The dependent supply source 247 generates the regulated sourcesignal 271 to include inverse components of the noise transients,thereby rendering them negligible.

FIG. 43 is a schematic block diagram of another embodiment of a sensingcircuit that includes the transient circuit 203, the comparator 265, thedependent current source 247, the analog to digital converter (ADC) 263and the digital to analog converter (DAC) 261 of FIG. 41 . The sensingcircuit further includes a second analog to digital converter (ADC) 283and a digital summing circuit 285. The ADC 283 converts the compensationsignal 207 to a digital signal 291. The digital summing circuit 285 sums(e.g., adds, averages, etc.) the digital signal 291 and the digitalsignal 269 to produce a combined digital signal 293. The digital summingcircuit may be implemented in a variety of ways. For example, thedigital summing circuit 285 includes an adder. As another example, thedigital summing circuit 285 includes an adder and a digital root meansquare (RMS) function. As another example, the digital summing circuit285 is a digital averaging circuit. As yet another example, the digitalsumming circuit 285 is weighted average circuit.

As a further example, the digital summing circuit 285 includes athreshold circuit and one of the adder, the digital averaging circuitand the weighted averaging circuit. The threshold circuit functions toprovide the digital signal 291 to the adder, digital averaging circuit,or the weighted averaging circuit when the digital signal 291 is above athreshold (e.g., representing a transient signal with an amplitude of 50mV or more) and to provide a zero digital signal to the adder, digitalaveraging circuit, or the weighted averaging circuit when the digitalsignal 291 is at or below the threshold.

The DAC 261 converts the combined digital signal 293 into the analogregulation signal 267. The dependent supply source 247 generates theregulated source signal 271 to include inverse components of the noisetransients, thereby rendering them negligible.

FIG. 44 is a schematic block diagram of another embodiment of a drivesense circuit 28-c coupled to a sensor 30. As previously discussed, thesensor 30 senses a condition 114 and causes an affect 219 on a referencesource signal 273. The drive sense circuit 28-c includes an operationalamplifier (op amp) 301, a current source 277, an analog to digitalconverter 263, a resistor R1 and a transistor T1.

The transistor T1 is coupled to op amp 301 as a source follower. Asconfigured, the transistor T1 and the op amp 301 function to keep thevoltage of the regulated source signal 273 substantially equal to thereference source signal 273. The reference source signal 273 is similarto reference signal 157 of one or more of FIGS. 14-18 .

As the impedance of the sensor 30 changes due to changes in thecondition 114, the impedance changes affect the current (I3) of theregulated source signal 271. Since the voltage of the regulated sourcesignal 271 is regulated to substantially match the voltage of thereference source signal 273, the current (I3) of the regulated sourcesignal 271 varies in accordance with the fixed voltage of the regulatedsource signal divided by the changing impedance of the sensor 30.

As the current (I3) of the regulated source signal 271 changes, the opamp 301 adjusts the comparison signal 345 to keep the voltage of theregulated source signal 271 substantially matching the voltage of thereference source signal 273. With the transistor T1 operated in theOhmic region, as the comparison signal 345 changes, the voltage (VR1)across resistor R1 changes based on changes to the current (I1) throughthe resistor R1. Current (I1) equals the current (I3) of the regulatedsource signal 271 plus the current (I2) of the current source 277. Sincethe current (I2) of the current source 277 is fixed, the current (I1)through the resistor R1 varies proportionally to the varying of thecurrent (I3) of the regulated source signal 271.

Thus, the error correction to keep the voltage of the regulated sourcesignal 271 substantially matching the voltage of the reference sourcesignal 273 is reflected in the changes in the current (I1) throughresistor R1. As the current (I1) varies, so does the voltage (VR1)across the resistor R1. The supply voltage (Vdd) less the voltage (VR1)provides an analog input voltage 333 for the analog to digital converter263. The analog to digital converter 263 converts the voltage at theanalog input voltage 333 into a digital sensed signal 309, which isrepresentative of the affect 219 that the sensor 30 has on the referencesource signal 273.

FIG. 45 is a schematic block diagram of another embodiment of a drivesense circuit 28-d coupled to a sensor 30. As previously discussed, thesensor 30 senses a condition 114 and causes an affect 219 on a referencesource signal 273. The drive sense circuit 28-d includes an operationalamplifier (op amp) 301, a current source 277, an analog to digitalconverter 263, and a transistor T1.

The op amp 301 is coupled as a unity gain amplifier. As configured, theop amp 301 functions to keep the voltage of the regulated source signal273 substantially equal to the reference source signal 273. Thereference source signal 273 is similar to reference signal 157 of one ormore of FIGS. 14-18 .

As the impedance of the sensor 30 changes due to changes in thecondition 114, the impedance changes affect the current (I3) of theregulated source signal 271. Since the voltage of the regulated sourcesignal 271 is regulated to substantially match the voltage of thereference source signal 273, the current (I3) of the regulated sourcesignal 271 varies in accordance with the fixed voltage of the regulatedsource signal divided by the changing impedance of the sensor 30.

As the current (I3) of the regulated source signal 271 changes, the opamp 301 operates to keep the voltage of the regulated source signal 271substantially matching the voltage of the reference source signal 273.As shown, the current (I1) through transistor T1 equals the current (I3)of the regulated source signal 271 (e.g., the current of the sensor 30)plus the current (I2) of the current source 277. Since the current (I2)of the current source 277 is fixed, the current (I1) through thetransistor T1 varies proportionally to the varying of the current (I3)of the regulated source signal 271 (e.g., current (I3) of the sensor30).

Thus, the error correction to keep the voltage of the regulated sourcesignal 271 substantially matching the voltage of the reference sourcesignal 273 is reflected in the changes in the current (I1) throughtransistor T1, which is biased to substantially remain the Ohmic regionvia the bias voltage 335. As the current (I1) varies, so does thevoltage (VT1) across the transistor T1. The supply voltage (Vdd) lessthe voltage (VT1) provides an analog input voltage 333 for the analog todigital converter 263. The analog to digital converter 263 converts thevoltage at the analog input voltage 333 into a digital sensed signal309, which is representative of the affect 219 that the sensor 30 has onthe reference source signal 273.

As may be used herein, the terms “substantially” and “approximately”provide an industry-accepted tolerance for its corresponding term and/orrelativity between items. For some industries, an industry-acceptedtolerance is less than one percent and, for other industries, theindustry-accepted tolerance is 10 percent or more. Other examples ofindustry-accepted tolerance range from less than one percent to fiftypercent. Industry-accepted tolerances correspond to, but are not limitedto, component values, integrated circuit process variations, temperaturevariations, rise and fall times, thermal noise, dimensions, signalingerrors, dropped packets, temperatures, pressures, material compositions,and/or performance metrics. Within an industry, tolerance variances ofaccepted tolerances may be more or less than a percentage level (e.g.,dimension tolerance of less than +/−1%). Some relativity between itemsmay range from a difference of less than a percentage level to a fewpercent. Other relativity between items may range from a difference of afew percent to magnitude of differences.

As may also be used herein, the term(s) “configured to”, “operablycoupled to”, “coupled to”, and/or “coupling” includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for an example of indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.

As may even further be used herein, the term “configured to”, “operableto”, “coupled to”, or “operably coupled to” indicates that an itemincludes one or more of power connections, input(s), output(s), etc., toperform, when activated, one or more its corresponding functions and mayfurther include inferred coupling to one or more other items. As maystill further be used herein, the term “associated with”, includesdirect and/or indirect coupling of separate items and/or one item beingembedded within another item.

As may be used herein, the term “compares favorably”, indicates that acomparison between two or more items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1. As maybe used herein, the term “compares unfavorably”, indicates that acomparison between two or more items, signals, etc., fails to providethe desired relationship.

As may be used herein, one or more claims may include, in a specificform of this generic form, the phrase “at least one of a, b, and c” orof this generic form “at least one of a, b, or c”, with more or lesselements than “a”, “b”, and “c”. In either phrasing, the phrases are tobe interpreted identically. In particular, “at least one of a, b, and c”is equivalent to “at least one of a, b, or c” and shall mean a, b,and/or c. As an example, it means: “a” only, “b” only, “c” only, “a” and“b”, “a” and “c”, “b” and “c”, and/or “a”, “b”, and “c”.

As may also be used herein, the terms “processing module”, “processingcircuit”, “processor”, “processing circuitry”, and/or “processing unit”may be a single processing device or a plurality of processing devices.Such a processing device may be a microprocessor, micro-controller,digital signal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, processing circuitry, and/or processing unitmay be, or further include, memory and/or an integrated memory element,which may be a single memory device, a plurality of memory devices,and/or embedded circuitry of another processing module, module,processing circuit, processing circuitry, and/or processing unit. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, cache memory, and/or any device that stores digital information.Note that if the processing module, module, processing circuit,processing circuitry, and/or processing unit includes more than oneprocessing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,processing circuitry and/or processing unit implements one or more ofits functions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory and/or memory element storing thecorresponding operational instructions may be embedded within, orexternal to, the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry. Still further notethat, the memory element may store, and the processing module, module,processing circuit, processing circuitry and/or processing unitexecutes, hard coded and/or operational instructions corresponding to atleast some of the steps and/or functions illustrated in one or more ofthe Figures. Such a memory device or memory element can be included inan article of manufacture.

One or more embodiments have been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claims. Further, the boundariesof these functional building blocks have been arbitrarily defined forconvenience of description. Alternate boundaries could be defined aslong as the certain significant functions are appropriately performed.Similarly, flow diagram blocks may also have been arbitrarily definedherein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence couldhave been defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claims. One of average skill in the art will alsorecognize that the functional building blocks, and other illustrativeblocks, modules and components herein, can be implemented as illustratedor by discrete components, application specific integrated circuits,processors executing appropriate software and the like or anycombination thereof.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with one or more other routines. In addition, a flow diagrammay include an “end” and/or “continue” indication. The “end” and/or“continue” indications reflect that the steps presented can end asdescribed and shown or optionally be incorporated in or otherwise usedin conjunction with one or more other routines. In this context, “start”indicates the beginning of the first step presented and may be precededby other activities not specifically shown. Further, the “continue”indication reflects that the steps presented may be performed multipletimes and/or may be succeeded by other activities not specificallyshown. Further, while a flow diagram indicates a particular ordering ofsteps, other orderings are likewise possible provided that theprinciples of causality are maintained.

The one or more embodiments are used herein to illustrate one or moreaspects, one or more features, one or more concepts, and/or one or moreexamples. A physical embodiment of an apparatus, an article ofmanufacture, a machine, and/or of a process may include one or more ofthe aspects, features, concepts, examples, etc. described with referenceto one or more of the embodiments discussed herein. Further, from figureto figure, the embodiments may incorporate the same or similarly namedfunctions, steps, modules, etc. that may use the same or differentreference numbers and, as such, the functions, steps, modules, etc. maybe the same or similar functions, steps, modules, etc. or differentones.

While the transistors in the above described figure(s) is/are shown asfield effect transistors (FETs), as one of ordinary skill in the artwill appreciate, the transistors may be implemented using any type oftransistor structure including, but not limited to, bipolar, metal oxidesemiconductor field effect transistors (MOSFET), N-well transistors,P-well transistors, enhancement mode, depletion mode, and zero voltagethreshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of theembodiments. A module implements one or more functions via a device suchas a processor or other processing device or other hardware that mayinclude or operate in association with a memory that stores operationalinstructions. A module may operate independently and/or in conjunctionwith software and/or firmware. As also used herein, a module may containone or more sub-modules, each of which may be one or more modules.

As may further be used herein, a computer readable memory includes oneor more memory elements. A memory element may be a separate memorydevice, multiple memory devices, or a set of memory locations within amemory device. Such a memory device may be a read-only memory, randomaccess memory, volatile memory, non-volatile memory, static memory,dynamic memory, flash memory, cache memory, and/or any device thatstores digital information. The memory device may be in a form asolid-state memory, a hard drive memory, cloud memory, thumb drive,server memory, computing device memory, and/or other physical medium forstoring digital information.

While particular combinations of various functions and features of theone or more embodiments have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent disclosure is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A sensing system comprises: a reference signalcircuit operable to generate a plurality of reference signals, wherein afirst reference signal of the plurality of reference signals includes afirst oscillating component at a first frequency; a plurality of drivesense circuits operably coupled to an array of sensors, wherein a firstdrive sense circuit of the plurality of drive sense circuits, whenoperably coupled to a first sensor of the array of sensors, is operableto: drive a first sensor signal via a first single line to the firstsensor of the array of sensors, wherein the first sensor signal isgenerated from a set of reference signals of the plurality of referencesignals; detect a change of the first sensor signal via the first singleline that is based on one or more electrical characteristics of thefirst sensor; generate a first signal representative of the change ofthe first sensor signal, wherein the first signal includes a set offrequency components, wherein the set of frequency componentscorresponds to the set of reference signals; a plurality of digitalfilters, wherein a set of digital filters of the plurality of digitalfilters is operable to filter the set of frequency components of thefirst signal to produce a set of frequency-dependent electricalcharacteristics of the first sensor; and a processing module operablycoupled to determine a frequency response of the first sensor based onthe set of frequency-dependent electrical characteristics of the firstsensor.
 2. The sensing system of claim 1 further comprises: theprocessing module is further operable to provide a control signal to thereference signal circuit; and the reference signal circuit is furtheroperable to generate the plurality of reference signals in accordancewith the control signal.
 3. The sensing system of claim 1, wherein thefirst drive sense circuit is further operable to: generate a smallmagnitude analog drive signal based on the set of reference signals;regulate the analog drive signal as an electrical characteristic of theone or more electrical characteristics of the first sensor varies;generate a change signal based on regulation of the analog drive signal;and generate the first signal based on the change signal.
 4. The sensingsystem of claim 1 further comprises: a second drive sense circuit of theplurality of drive sense circuits, when coupled to a second sensor ofthe array of sensors, is operable to: drive a second sensor signal via asecond single line to the second sensor of the array of sensors; detecta change of the second sensor signal via the second single line that isbased on one or more electrical characteristics of the second sensor;generate a second signal representative of the change of the secondsensor signal, wherein the second signal includes a second set offrequency components, wherein the second set of frequency componentscorresponds to a second set of reference signals of the plurality ofreference signals; a second set of digital filters of the plurality ofdigital filters is operable to filter the second set of frequencycomponents of the second signal to produce a second set offrequency-dependent electrical characteristics of the second sensor; andthe processing module is further operably coupled to determine afrequency response of the second sensor based on the second set offrequency-dependent electrical characteristics of the first sensor. 5.The sensing system of claim 4 further comprises: the processing moduleis further operably coupled to determine a frequency response of thearray of sensors based on the second sensor based on the set offrequency-dependent electrical characteristics of the first sensor andthe second set of frequency-dependent electrical characteristics of thefirst sensor.
 6. The sensing system of claim 5 further comprises: theprocessing module is further operably coupled to determine aself-capacitance frequency for at least some of the sensors of the arrayof sensors based on the frequency response of the array of sensors. 7.The sensing system of claim 5 further comprises: the processing moduleis further operably coupled to determine a plurality ofmutual-capacitance frequencies for at least some of the sensors of thearray of sensors based on the frequency response of the array ofsensors.
 8. The sensing system of claim 1 further comprises: the arrayof sensors.
 9. A touch screen comprises: a plurality of electrodes; areference signal circuit operable to generate a plurality of referencesignals, wherein a first reference signal of the plurality of referencesignals includes a first oscillating component at a first frequency; aplurality of drive sense circuits operably coupled to the plurality ofelectrodes, wherein a first drive sense circuit of the plurality ofdrive sense circuits, when operably coupled to a first electrode of theplurality of electrodes, is operable to: drive a first electrode signalvia a first single line to a first electrode of the plurality ofelectrodes, wherein the electrode signal is generated from a set ofreference signals of the plurality of reference signals; detect a changeof the first electrode signal via the first single line that is based onone or more electrical characteristics of the first electrode of theplurality of electrodes; generate a first signal representative of thechange of the first electrode signal, wherein the first signal includesa set of frequency components, wherein the set of frequency componentscorresponds to the set of reference signals; a plurality of digitalfilters, wherein a set of digital filters of the plurality of digitalfilters is operable to filter the set of frequency components of thefirst signal to produce a set of frequency-dependent electricalcharacteristics of the first electrode; and a processing module operablycoupled to determine a frequency response of the first electrode basedon the set of frequency-dependent electrical characteristics of thefirst electrode.
 10. The touch screen of claim 9 further comprises: theprocessing module is further operable to provide a control signal to thereference signal circuit; and the reference signal circuit is furtheroperable to generate the plurality of reference signals in accordancewith the control signal.
 11. The touch screen of claim 9, wherein thefirst drive sense circuit is further operable to: generate a smallmagnitude analog drive signal based on the set of reference signals;regulate the analog drive signal as an electrical characteristic of theone or more electrical characteristics of the first electrode varies;generate a change signal based on regulation of the analog drive signal;and generate the first signal based on the change signal.
 12. The touchscreen of claim 9 further comprises: a second drive sense circuit of theplurality of drive sense circuits, when coupled to a second electrode ofthe plurality of electrodes, is operable to: drive a second electrodesignal via a second single line to the second electrode of the pluralityof electrodes; detect a change of the second electrode signal via thesecond single line that is based on one or more electricalcharacteristics of the second electrode of the plurality of electrodes;generate a second signal representative of the change of the secondelectrode signal, wherein the second signal includes a second set offrequency components wherein the second set of frequency componentscorresponds to a second set of reference signals of the plurality ofreference signals; a second set of digital filters of the plurality ofdigital filters is operable to filter the second set of frequencycomponents of the second signal to produce a second set offrequency-dependent electrical characteristics of the second electrodeof the plurality of electrodes; and the processing module is furtheroperably coupled to determine a frequency response of the secondelectrode of the plurality of electrodes based on the second set offrequency-dependent electrical characteristics of the first electrode ofthe plurality of electrodes.
 13. The touch screen of claim 12 furthercomprises: the processing module is further operably coupled todetermine a frequency response of the plurality of electrodes based onthe second electrode of the plurality of electrodes based on the set offrequency-dependent electrical characteristics of the first electrode ofthe plurality of electrodes and the second set of frequency-dependentelectrical characteristics of the first electrode of the plurality ofelectrodes.
 14. The touch screen of claim 13 further comprises: theprocessing module is further operably coupled to determine aself-capacitance frequency for at least some of the electrodes of theplurality of electrodes based on the frequency response of theelectrodes.
 15. The touch screen of claim 13 further comprises: theprocessing module is further operably coupled to determine a pluralityof mutual-capacitance frequencies for at least some of the electrodes ofthe plurality electrodes based on the frequency response of theelectrodes.
 16. A touch screen controller comprises: a reference signalcircuit operable to generate a plurality of reference signals, wherein afirst reference signal of the plurality of reference signals includes afirst oscillating component at a first frequency; a plurality of drivesense circuits operably coupled to a plurality of electrodes of a touchscreen, wherein a first drive sense circuit of the plurality of drivesense circuits, when operably coupled to a first electrode of theplurality of electrodes, is operable to: drive a first electrode signalvia a first single line to the first electrode of the plurality ofelectrodes; detect a change of the first electrode signal via the firstsingle line that is based on one or more electrical characteristics ofthe first electrode of the plurality of electrodes; generate a firstsignal representative of the change of the first electrode signal,wherein the first signal includes a set of frequency components, whereinthe set of frequency components corresponds to a set of referencesignals of the plurality of reference signals; a plurality of digitalfilters, wherein a set of digital filters of the plurality of digitalfilters is operable to filter the set of frequency components of thefirst signal to produce a set of frequency-dependent electricalcharacteristics of the first electrode; and a processing module operablycoupled to determine a frequency response of the first electrode basedon the set of frequency-dependent electrical characteristics of thefirst electrode.
 17. The touch screen controller of claim 16 furthercomprises: the processing module is further operable to provide acontrol signal to the reference signal circuit; and the reference signalcircuit is further operable to generate the plurality of referencesignals in accordance with the control signal.
 18. The touch screencontroller of claim 16, wherein the first drive sense circuit is furtheroperable to: generate a small magnitude analog drive signal based on theset of reference signals; regulate the analog drive signal as anelectrical characteristic of the one or more electrical characteristicsof the first electrode varies; generate a change signal based onregulation of the analog drive signal; and generate the first signalbased on the change signal.
 19. The touch screen controller of claim 16further comprises: a second drive sense circuit of the plurality ofdrive sense circuits, when coupled to a second electrode of theplurality of electrodes, is operable to: drive a second electrode signalvia a second single line to the second electrode of the plurality ofelectrodes; detect a change of the second electrode signal via thesecond single line that is based on one or more electricalcharacteristics of the second electrode of the plurality of electrodes;generate a second signal representative of the change detected on thesecond electrode signal, wherein the second signal includes a second setof frequency components wherein the second set of frequency componentscorresponds to a second set of reference signals of the plurality ofreference signals; a second set of digital filters of the plurality ofdigital filters is operable to filter the second set of frequencycomponents of the second signal to produce a second set offrequency-dependent electrical characteristics of the second electrodeof the plurality of electrodes; and the processing module is furtheroperably coupled to determine a frequency response of the secondelectrode of the plurality of electrodes based on the second set offrequency-dependent electrical characteristics of the first electrode ofthe plurality of electrodes.
 20. The touch screen controller of claim 19further comprises: the processing module is further operably coupled todetermine a frequency response of the plurality of electrodes based onthe second electrode of the plurality of electrodes based on the set offrequency-dependent electrical characteristics of the first electrode ofthe plurality of electrodes and the second set of frequency-dependentelectrical characteristics of the first electrode of the plurality ofelectrodes.
 21. The touch screen controller of claim 20 furthercomprises: the processing module is further operably coupled todetermine a self-capacitance frequency for at least some of theelectrodes of the plurality of electrodes based on the frequencyresponse of the electrodes.
 22. The touch screen controller of claim 20further comprises: the processing module is further operably coupled todetermine a plurality of mutual-capacitance frequencies for at leastsome of the electrodes of the plurality electrodes based on thefrequency response of the electrodes.